Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium [1 ed.] 9781614992424, 9781614992417

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Case Studies in Advanced Engineering Design

Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

The 1st International Symposium ‘Case Studies in Advanced Engineering Design’ was held on 18-19 November 2010 at the Aula congress centre & the faculty building of Industrial Design Engineering, Delft University of Technology, Delft, Netherlands

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Organised by the Product Engineering section of the Faculty of Industrial Design Engineering with the support of the platform Delft Design & Engineering, Delft University of Technology

Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Case Studies in Advanced Engineering Design Proceedings of the 1st International Symposium Edited by Christos Spitas, Vasilios Spitas, Mohammadreza Rajabalinejad

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

Delft University Press

Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

© 2013 The authors and IOS Press. All rights reserved. ISBN 978-1-61499-241-7 (print) ISBN 978-1-61499-242-4 (online)

Cover photograph: Radiograph of Fragment A of the Antikythera Mechanism. Reproduced with permission © 2005 Antikythera Mechanism Research Project

Published by IOS Press under the imprint Delft University Press

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LEGAL NOTICE The publisher is not responsible for the use which might be made of the following information. PRINTED IN THE NETHERLANDS

Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved.

Table of contents Preface & acknowledgements ............................................................ ix Editorial address.................................................................................. 1 Introduction ......................................................................................... 2 Indexed summaries of case studies ..................................................... 5 1. Barone M., Advanced engineering design as practiced today from the view point of the CERN Industrial Liaison Officer ............. 9 Summary ......................................................................................... 9 1.1. Introduction: CERN and its Large Hadron Collider ................ 9 1.2. The Large Hadron Collider (LHC) ........................................ 10 1.3. Some technological issues: Pros ............................................ 11 1.4. LHC design flaws .................................................................. 17 1.5. Conclusion ............................................................................. 18 Bibliography ................................................................................. 18 Topics for discussion and self-study ............................................. 19 2. Katsikas S., An innovative system for vessels monitoring, diagnosis and prognosis, and the challenges to be faced .................. 23 Summary ....................................................................................... 23 2.1. Introduction ............................................................................ 23

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2.2. Business model ...................................................................... 24 2.3. Problem identification and market study ............................... 25 2.4. The concept of Laros ............................................................. 31 2.5. Electronics system ................................................................. 32 2.6. Energy harvesting .................................................................. 34 2.7. Collaboration.......................................................................... 35 Topics for discussion and self-study ............................................. 37 3.

Editorial, Future challenges for road transport ......................... 43 Summary ....................................................................................... 43

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

4. Garlasché M., Tolerances optimisation in the mechanical design of components for a medical Linac ................................................... 47 Summary ....................................................................................... 47 4.1. Introduction to proton therapy ............................................... 47 4.2. LIGHT.................................................................................... 49 4.3. The First Unit and its components ......................................... 51 4.4. Basic theory for cell design and production .......................... 54 4.5. Old and new tolerance definition procedures ........................ 61 4.6. Numerical case evaluation ..................................................... 66 4.7. Conclusion ............................................................................. 68 Bibliography ................................................................................. 68 Topics for discussion and self-study ............................................. 69 5.

Draad A., Design of the Océ ColorWave 600 carriage ............. 72 Summary ....................................................................................... 72 5.1. Introduction ............................................................................ 72 5.2. Principle of the inkjet ............................................................. 73 5.3. Mechanical layout inkjet printer ............................................ 75 5.4. Design aspects of the carriage ................................................ 76 5.5. Self-positioning ...................................................................... 78 5.6. Thermal design....................................................................... 83 5.7. Design phase .......................................................................... 85 5.8. Conclusion ............................................................................. 88

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Topics for discussion and self-study ............................................. 90 6. Mellace C., Mechanical optimisation of a RF coupling system for a medical Linac by means of FMEA ........................................... 93 Summary ....................................................................................... 93 6.1. Hadron therapy....................................................................... 93 6.2. ADAM’s technological innovations ...................................... 97 6.3. Failure Modes and Effects Analysis (FMEA) and Failure Modes, Effects and Criticality Analysis (FMECA) ...................... 99 6.4. Case analysis: Mechanical optimisation of a RF coupling system for a medical Linac through FMEA ................................ 101

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

6.5. Upgrades and improvements: Towards the RF coupling system ‘Version 2010’ ............................................................................ 109 6.6. Conclusion: A comparison between ‘Version 2001’ and ‘Version 2011’ ............................................................................ 115 Bibliography ............................................................................... 117 Topics for discussion and self-study ........................................... 118 7.

van Gorp E., Dyneema® for ballistic applications ................. 121 Summary ..................................................................................... 121 7.1. Design of a polyethylene yarn ............................................. 121 7.2. Design of UD product for ballistic applications .................. 133 Bibliography ............................................................................... 140 Topics for discussion and self-study ........................................... 141

8. Russchenberg H., From raindrop to radar and from needs to technology ....................................................................................... 144 Summary ..................................................................................... 144 8.1. Introductory context: Climate and the weather .................... 144 8.2. What radar measures ............................................................ 149 8.3. Radar designs ....................................................................... 159 8.4. The role of the engineer ....................................................... 161 Topics for discussion and self-study ........................................... 163 9.

Albers A., Océ VarioPrint 6000 platform design ................... 166 9.1. History.................................................................................. 167 9.2. Contact transfer .................................................................... 169

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9.3. Duplex .................................................................................. 172 9.4. Contact nibs ......................................................................... 175 9.5. Photoconductor belts ............................................................ 177 9.6. The speed control layout ...................................................... 178 Topics for discussion and self-study ........................................... 181 10. Coman C., Need to know and obligation to share in NATO Intelligence, Surveillance and Reconnaissance (ISR) .................... 182 Summary ..................................................................................... 182 10.1. Background context ........................................................... 182

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

10.2. Introduction to the MAJIIC project ................................... 183 10.3. MAJIIC project architecture and development .................. 187 10.4. Spiral development ............................................................ 192 10.5. Future planning .................................................................. 194 Topics for discussion and self-study ........................................... 195 11.

Spitas C., Spitas V., On engineering design methodology .. 196

Summary ..................................................................................... 196 11.1. Introduction ........................................................................ 196 11.2. Results and discussion of a survey..................................... 198 11.3. Discussion of the case studies ............................................ 203 Bibliography ............................................................................... 206 Editorial summary of main conclusions ......................................... 209 Appendix 1 ...................................................................................... 210 Appendix 2 ...................................................................................... 214 Appendix 3 ...................................................................................... 215 Modelling of ideas: Fundamental considerations ....................... 215 Graphical representation ............................................................. 217 Operations: Formal use of synaptic networks ............................. 217

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Establishing and validating relationships and causalities ........... 219

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Preface & acknowledgements

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Shortly after we almost simultaneously moved to our current academic positions in the Delft University of Technology and the National Technical University of Athens respectively, and finding ourselves both engaged in very similar ways in the field of engineering design, we resolved to undertake, next to our longstanding scientific research collaboration dating back to our PhD studies at the National Technical University of Athens, also some joint dissemination efforts to bring our industrial and academic networks and institutions closer together and instigate a valuable cross-talk at a European level. Case Studies in Advanced Engineering Design (CSiAED), first the symposium and now this book, have been fruits of this. After the symposium, the first in an envisioned series, we were fortunate to have Dr. Rajabalinejad, a new assistant professor in Christos’ team, join our editorial effort and help with an otherwise unwieldy process of collecting and laying out materials. Without him we would, no doubt, still be looking helplessly at these same materials. During this time, we also joined our forces with those of other enthusiastic peers in European academia and founded the European Academic Network of Product Engineering (EAN-PE), promising to take our joint research and dissemination efforts even further. With the 2nd CSiAED now about to take place in Athens 2 ½ years after the 1st, the present book therefore arrives at a time when the vision behind it has consolidated much more and it looks like a critical mass has been reached. At the same time, we must not fail to acknowledge those who, in the fledgling beginnings of CSiAED, contributed with their inspiration, ideas, support and work: We would like to extend our gratitude towards Prof. Dr. Cees de Bont, Prof. Dr. Michel van Tooren and Prof. Dr. Tetsuo Tomiyama of the Delft University of Technology and members of the Platform Delft Design & Engineering for their strong support and contribution to the original symposium, and towards Prof. Karel Luyben, Rector Magnificus, also for his kind support.

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

From the Product Engineering team organising the event special mention is due to the many efforts and good initiative of Mr. Marco Bolleboom, Project Support Officer. Initial transcriptions of some of the audio recordings were executed by Mr. Nikolaos Kazazakis and Mr. Amin Amani, lecturers and PhD candidates. Lastly, and most of all, the editors would like to extend their grateful acknowledgement of the substantial effort, time, investment and enthusiasm from all the invited speakers and authors and their respective organisations, who eagerly helped make the CSiAED symposium a reality and without whom this unique account of proceedings could never have existed. May 2013 Vasilios Spitas

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Christos Spitas

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved.

Editorial address A lot is being said about Engineering Design. It is is

correct, and yet much of it

suspect. It is suspect because it is based on anecdotal evidence,

intuition, personal experience, assumptions, and extrapolations. It is suspect because it is based on experiments on methodology that have been proven to give

non-repeatable results. It

is suspect because, when one is deeply engaged in design, one does not

record

the trajectory of one’s thought, only the results. It is suspect because we keep

secrets. At Delft and Athens we believe in the

truth. We believe in science.

We believe in factual

data and in reproducible observations. We believe in knowledge and openness. We believe in

dissemination as a basic condition of understanding by the collectively thinking organism that is called global human society. But above all we believe in

excellence

. We know from our

experience that this excellence, as far as Advanced Engineering Design is

companies and organisations that continuously invest in and have internalised the value and importance of Copyright © 2013. IOS Press, Incorporated. All rights reserved.

concerned, is to be found in leading

R&D. We believe that they have something important to say and that they want to say it. Methodology cannot be patented and benefits noone if it is not taught efficiently in the universities.

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved.

Introduction

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This was the address on the 18th of November 2010 that started the first in a line of symposia by TU Delft and NTU Athens titled ‘Case Studies in Advanced Engineering Design’. What followed this address was a sequence of ten invited lectures, each studying a real case of advanced engineering design from international organisations of widely different missions, structures and sizes. The hypothesis was that deep down, under all the varied sorts of products and product lines, processes and organisational schemes, there would be one single unified fundamental manner in which engineering design is carried out. We were somewhat bold in inviting CERN, Prisma Electronics, DAF, Océ-Canon, ADAM, IRCTR/ TU Delft, DSM and NATO, which cover a wide spectrum of research, industrial and defence system applications, and asking them to focus on material products, (immaterial) processes as products, and processes as ways to design products and knowledge. We invited such variety of case studies not because we needed the different topics, but because we needed the different viewpoints. And indeed the presentations revealed a richness in this respect that justifies the bold choice of case studies. In hindsight, our original hypothesis of a unified fundamental manner of engineering design also seems to be justified, at least insofar as we witnessed a deeper and natural shared understanding between the experts and the other participants of the symposium, where everyone was ‘on familiar ground’ and recognising the reasons and goals behind each other’s design process, as explained in their case studies, even though they knew almost nothing of each other’s technology or domain of activity. During the symposium we endeavoured to highlight this unity a bit further through editorial commentaries, herein condensed into a final section titled ‘On engineering design methodology’. To further penetrate the topic we asked the participants to reply to a questionnaire survey with regard to some aspects of the design process, the findings of which we also report in the same section. On the second day of the symposium, speakers and participants met in

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Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

workshops titled ‘Knowledge-based decision making in Advanced Engineering Design’ and ‘On the how of transformations: from academic knowledge to industrial practice and from student to competent engineer.’ The significant findings from these discussions have further informed and been integrated into the concluding editorial summary. The discussions themselves were valuable but proved too complex and detailed to report ad verbatim in these proceedings.

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The bulk of this book of proceedings comprises of course the case studies themselves, which we invited the speakers to commit to paper after the symposium, as faithfully and in detail as the intellectual property rights and confidentiality interests of their organisations would permit. We managed to get 9 out of the 10 case studies on this volume; for three of them (Cases 7, 8 and partly 10), the specific form of their narratives prompted us to transcribe them from the presentation (nearly ad verbatim, with only minor editing for readability), to keep them effective. Each one of the case studies is worth reading in its own right; depending on the reader’s background, different insights can be gained: 1) The university student aspiring to be a designer will benefit from reading true stories of advanced engineering design, learning to recognise the patterns by which it manifests itself on a product, process and organisational level. By analysing and internalising these patterns, he will have something to emulate in his first steps as a designer. 2) The young practitioner, already employed in some domain of engineering design, will be able to cross-reference the daily and not-so-daily practices around him to those studied in this book. The case studies are primarily meant to be studied, analysed, dissected, criticised, learned from, and even improved on. They themselves have been results of such processes within the organisations that report them; as such, reading this book will be a process of rediscovery, essential to the conscious growth of a young practitioner. 3) The researcher will no doubt find value, like the editors already did, in the explicit uncensored accounts of engineering design projects; this is potentially a resource for the inspiration of theories that aim to understand and perhaps

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Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

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even explain engineering design as a real and complex process, as well as a testing ground for existing theories. 4) Finally, there is the experienced practitioner, perhaps an expert. There is evidently little room for fundamental learning here, or even the occasional surprise. Yet, the experienced practitioner can benefit from the (re)inspiration of seeing how others are realising similar design processes, how they are placing the focus. Too often we settle in the successful ways of our daily practice, to the point that we miss the opportunity to revisit and perhaps to fundamentally improve our approach. The book can thus serve as a stimulus for sharper selfreflection. Because the input comes not from an academic instructor, but from the lips –or pens– of one’s peers, the cases told carry much more immediacy and credibility. Based on the feedback by most of the invited speakers, being exposed to each other’s case studies had such an effect on them. Ultimately, we believe that the value of these case studies lies in reading them in parallel and contrasting them to each other and to one’s own experience, wherever that is possible. Some of them are explicitly rich in methodology, even in some cases showing the application of specific methods, others are richer in experience, while others are more explicit at drawing conclusions and guidelines. A set of ‘Topics for discussion and self-study’ are provided by the editors after each case study, aiming mostly to stimulate further essential mental processing. To this end, appropriate supporting methodology is also offered in a dedicated appendix (Appendix 3). Answers are not provided. This book of proceedings is not about serving ready-made conclusions, or a ‘how to’-guide of advanced engineering design. It hopes to serve as a ‘sharp radiography’ of current practices, being neither the ultimate diagnosis nor a prognosis. It is a reference, a starting point for the kind of questioning and dialectic that makes engineering design such a uniquely fascinating, challenging and rewarding human endeavour.

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved.

Indexed summaries of case studies An abstracted review of the main processes that were reported in the case studies is presented hereafter. This is intended as a reading guide, to direct attention to specific aspects of interest particular to each case study. More detailed elaboration of the topics follows in the subsequent sections. 1. European Centre for Nuclear Research (Michele Barone): Advanced engineering design as practiced today from the viewpoint of the CERN Industrial Liaison Officer

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The presentation shows how the mission statement of CERN drives different synergistic research and supporting design activities centred on overcoming technical challenges beyond the state of the art. Coupled multi-scale problems including high accuracy demands over large dimensions, high power levels and closely maintained cryogenic temperatures form the core context of the design and development process. Couplings appear not only on the level of physical phenomena, but also in the design process itself, with design, quality assurance, cost requirements, production and procurement, operational deployment and contingency handling closely connected. The criticality of engineering design choices is further demonstrated by analysis of operational failures. 2. Prisma Electronics SA (Serafeim Katsikas): An innovative system for vessels monitoring, diagnosis and prognosis, and the challenges to be faced The case study shows how the mission statement of Prisma Electronics in consideration of its resident technological field of expertise drives the forming of its business model through a learning and feedback process with the market and selected stakeholders. Through this process, needs and opportunities are identified and assessed, a clear target problem is defined and product development commences in a defined framework of requirements, constraints, both at a system level (system architecture) and at a module level, with a

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

clear identification of the interconnections that allow this system decomposition. Drivers are identified for the engineering choices, with enabling technologies being critical input. The development team structure is determined by scaling the technical fields in terms of importance, which decides the scope of in-house development and the actual synthesis of the working groups. Well-defined collaborations with technical institutes and other companies are instrumental. The significance and details of operational planning are discussed. 3. DAF Trucks NV (Jack Martens): Future challenges for road transport The presentation showcased how DAF trucks conducts its development process in parallel through technology projects and shorter term product development projects receiving input from the technology projects. Ideas funnel through stage-gates into roadmaps anticipating important trends for the coming decade, and finally technology projects are selected based on the identification and prioritisation of the most critical aspects and initiated. Drivers for product development in the project definition phase are the general requirements for performance improvement and cost reduction, as well as other aspects contributing to the program of wishes. Through stage-gate management, project definition is succeeded by the concept phase, the engineering phase and the volume validation phase.

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4. ADAM SA (Marco Garlasché): Tolerance optimisation for mechanical design of LIGHT components The case study illustrates how in the engineering development process in ADAM the product goal is decomposed and evaluated in the context of operation and re-evaluated in light of the emerging possibilities and impossibilities. Both technical and economical reasons drive the design process. Prototyping serves to prove concepts and to push the industrialisation level, which brings forward the coupling between optimal industrialisation and optimal design functionality goals. Systems decomposition serves to manage complexity and facilitate modelling. Design considers cause-andeffect relations in the involved physical phenomena, together with engineering uncertainty and tolerances. In particular sensitivity to uncertainty is an important criterion in design choices and a cyclic 6

Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

process is followed where designs are analysed and redesigned until convergence to the design goals. 5. Océ-Technologies BV (Aswin Draad): Design Océ ColorWave 600 carriage The discussion explains key considerations pertinent to the design of the ColorWave 600 printer carriage, which transports the print heads accurately during printing. Key challenge was the coupling of different functions with respect to the design goals, presenting various techno-economical challenges, such that a truly integrated process had to be followed. Positioning of the print heads, especially self-positioning, and thermal aspects are discussed which have largely shaped the design of the carriage. The case study shows how the transition is made from technical working principles to prototypes and mature validated designs, through extensive use of modelling and experimental testing and validation and in consideration of couplings. 6. ADAM SA (Claudio Mellace): Optimisation of a Coupling System for a Linac This case study looks at engineering design as an optimisation based on risk management, applying Failure Modes and Effects Analysis (FMEA); the subject of study is the coupling system of a linear accelerator for proton therapy treatments. Functional analysis and targeted use of modularity lie at the heart of the process illustrated.

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7. DSM Dyneema (Egbert van Gorp): Dyneema® for ballistic applications The case study concerns the design and development of the Dyneema® product line and specifically its application in ballistic protection. It illustrates how a random process of discovery can trigger the development of an innovative product line. Ballistics is discussed as one of the spin-off applications of the developed product, thus illustrating the hierarchy of products building up a product line. The case study finally expands into the change in the value chain and approach to project management that this development necessitated, vividly illustrating the couplings that govern an advanced engineering design process.

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

8. IRCTR (Herman Russchenberg): From raindrop to radar The presentation narrated the development of advanced radars for weather monitoring. It closely traces the cause-and-effect relationships that drive advanced engineering design from societal problems to science to design and product development to address the original societal problems. The case study shows how engineering design works on the basis of scientific models, specially developed to analyse and parameterise the phenomena employed in the design. 9. Océ-Technologies BV (Ton Albers): Océ VP6000 Platform Design This case study illustrates how the (re)use of prior art, modularity, and the affordances from the emergence of new enabling technologies interact to make a dynamic landscape for the development of a new product, as in the case of the Océ VP6000 Platform Design. Modelling is shown to be an integral part of the design process. Different technological considerations and the related decisions are explored, illustrating the application of this knowledgebased approach.

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10. NATO (Cristian Coman): Need to Know and Obligation to Share in NATO ISR This case study of the MAJIIC project is an illustration of how multiscale systems-level engineering design can be. It is the goal of the engineering design process to align goals, stakeholders and technology in an effective architecture. The role of abstraction and standardisation is illustrated. The case study serves well to illustrate the role of systems architecture in engineering design, and how the complexity and interfacing challenges between different architectural modules, often developed by different vendors, is managed to good effect. The spiral nature of the development process is also highlighted, as knowledge and design manifestations evolve through different project phases and subsequent projects over time.

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Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved. doi:10.3233/978-1-61499-242-4-9

1. Advanced engineering design as practiced today from the view point of the CERN Industrial Liaison Officer Barone M. (Michele) Industrial Liaison Officer, European Centre for Nuclear Research (CERN), Geneva, www.cern.ch

Summary After an introduction about CERN, a brief description of the Large Hadron Collider (LHC) it is reviewed. Pros and cons of a few advanced engineering design cases are taken in consideration together with the involvement of the European Industry. The conclusion is that the LHC project has been an important driving force for Innovation in European Industry.

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1.1. Introduction: CERN and its Large Hadron Collider CERN, the European Organization for Nuclear Research, is an intergovernmental organisation with 20 Member States. Its seat is in Geneva, but its premises are located on both sides of the FrenchSwiss border. CERN’s mission is to push back the frontiers of knowledge (e.g. the secrets of the Big Bang …what was the matter like within the first moments of the Universe’s existence?), to develop new technologies for accelerators and detectors, Information Technology (the Web and the GRID, Medicine - diagnosis and therapy), to train scientists and engineers of tomorrow. To enable international collaboration in the field of high-energy particle physics research, it designs, builds and operates particle accelerators and the associated experimental areas. At present more than 10.000 scientific users from research institutes all over the world are using CERN’s installations for their experiments. The accelerator complex at CERN is a succession of machines with increasingly higher energies,

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Barone M. Advanced engineering design as practiced today

injecting a particle beam each time into the next accelerator, bringing the beam to an increasingly higher energy level. Protons are obtained by removing electrons from hydrogen atoms, then they are injected from the linear accelerator (LINAC2) into the PS Booster, then to the Proton Synchrotron (PS), followed by the Super Proton Synchrotron (SPS), before reaching the Large Hadron Collider at the energy of 450GeV. Protons circulate in the LHC for 20 minutes before to reach the maximum energy of 7 TeV/ beam. Lead ions for the LHC start from a source of vaporised lead and enter LINAC3 before being collected and accelerated into the Low Energy Ion Ring (REIR).They then follow the same route to maximum acceleration as the protons.

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The flagship of the complex is the Large Hadron Collider (LHC) as presented in Figure 1.1.

Figure 1.1: Accelerators complex (not to scale) and the chain/ sequence of accelerators

1.2. The Large Hadron Collider (LHC) The LHC is based on 1232 double aperture superconducting dipole magnets, equivalent to 2864 single dipoles, operating up to 9 Tesla. The machine also incorporates about 500 “two-in-one” superconducting quadrupole magnets with a gradient of more 250T/m. Moreover there are more than 400s.c.corrector magnets of

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Barone M. Advanced engineering design as practiced today

many types. In operation the machine is involving the cooling down to 1.9K of 40.000 tons of material. The LHC is installed in the existing 27 km circumference tunnel, about 100 m underground, previously housing the Large Electron Positron Collider (LEP).The beam stored energy is 36MJoules. The beams are crossing in 4 points around which very large particle detectors are built. The starting point of the project is considered March 1984, but it was approved in 2000 and inaugurated in September 2008.Its final costs has been 4.6 billion of Swiss francs, including the contribution from States not Members of the Organization. It has been a challenging project from technical point of view and has proved to be an enriching experience for the participants.

1.3. Some technological issues: Pros

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The LHC construction, because of the approved budget, had to make the maximum use of the existing infrastructure in order to reduce the total cost. This implied some constraints on the technical point of view: since the tunnel hosting the new accelerator was the old 27km of the LEP era, it was not possible to modify it therefore the equipment had to be mounted in its 3.8m diameter. An LSC magnet occupies a considerable amount of space because of its cryostat; therefore it was impossible to fit in the same tunnel two independent rings as in the case of the Superconducting Super Collider proposed in USA as shown in Figure 1.2.

Figure 1.2: Schematic View of the SSC

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Barone M. Advanced engineering design as practiced today

A novel design with two rings separated by only19cm inside a common yoke and cryostat was developed: it was called the ‘two-inone’ approach. Figure 1.3 shows a schematic of a typical element.

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Figure 1.3: Structure of cryodipole The sensitivity of the forces acting on the cold masses (because of the changes during the cool-down) to the tolerances on all major components like collars laminations, inserts etc., has been checked by Finite Element Analysis computation by applying statistical methods in fact about 3000 geometries have been computed. Just to mention some figures, the forces acting on the coils are of 15 MPa and to avoid any distortion of them which could trigger a quench, 12 millions of non-magnetic collars with a tolerances from ±0.02 to 0.03mm have been produced by the European Industry. The total dipole length is 15m.This version, has been a real challenge and it generated a saving of 10% of the total project cost (4.6Gchf). The involvement of the Industry since the beginning of the project in 1984 has produced good results. Three companies have been in charge of the construction of the LHC’s superconducting dipoles: the French consortium Alstom MSA-Jeumont, the Italian firm Ansaldo Superconduttori and the German company Babcook Noell Nuclear. Each has provided one-third of the 12248 magnets including a preseries. A good uniformity in the dipoles mass production was found and one manufacturer delivered 1 year in advance. Figure 1.4 shows a typical dipole having a weight of 30 tons.

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Barone M. Advanced engineering design as practiced today

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Figure 1.4: Lowering of dipole into the tunnel Another example of Advanced Engineering case is given by the Compact Muon Solenoid (CMS) detector at point 5. The experimental program for the LHC began in March 1992 with a meeting in Evian-les Bains, near the French part of Lake of Geneva during which, the CMS Collaboration presented an Expression of Interest. The construction of it has presented formidable challenges from the technological, engineering, organisational and financial point of view. The construction has also required the pooling of the resources and talent of a large number of people as well as the involvement of the World Industry. CMS is formed by more than 2500 scientists and engineers from 180 Institutions in 38 countries around the world. The CMS detector is inspired by the LEP experiment; it has an onionlike structure with a succession of detectors both in the barrel and in the forward regions to determining the event topology, the nature and the energy of emerging particles. The momentum of the charged tracks is derived from the curvature of a strong magnetic field; the particle identification is made by a succession of electromagnetic and hadronic calorimeter followed by a Muon detector. Figure 1.5 is a schematic of the slice of the transverse cut through CMS illustrating the identification of the particles produced in the proton-proton collisions.

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Barone M. Advanced engineering design as practiced today

Figure 1.5: Slice of transverse cut through CMS showing particle interactions

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More precisely, the magnet system consists of a 4 Tesla Solenoid Superconducting Coil, having a 6m free bore,13m length, enclosed in a return Yoke, comprising the Barrel Yoke and the two End-Cap Yokes. The return Yoke is designed as a regular twelve-side structure. The main dimensions of the complete detector are: length 21m, outer diameter14.8m and a total mass 12.500 tons. Remarkable challenges were faced during the construction of this massive detector: it was built in modules and subsequently assembled inside a cavern 100m below the surface. Already at the conceptual design stage 20 years ago, it was decided to divide the massive flux-return iron yoke of the solenoid in sections allowing the construction and the assembly in stages. Figure 1.6 shows the detector sectioned in its parts.

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Figure 1.6: CMS detector in slices The yoke was assembled in a large surface building specially conceived for this purpose and equipped with a large gantry crane constructed on the outside of the building to lower the heavy elements of the detector in 15 pieces. See Figure 1.7.

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Barone M. Advanced engineering design as practiced today

Figure 1.7: CMS gantry installation

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The heaviest slice had a weight of 1920 tons. For the lowering operation, elements were suspended by four massive cables each with 55 strands, and attached to a step-by step hydraulic jacking system. Each operation took around 10 hours. Figure 1.8 shows the lowering of the final element.

Figure 1.8: Lowering of the final element into the CMS cavern Many have been the advantages in planning an experiment in such way: time was saved by working simultaneously on the detector while the experimental cavern was being excavated, fewer risks working at the surface in a more spacious area, each element and all elements together could be tested before lowering. When safely

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Barone M. Advanced engineering design as practiced today

positioned in the cavern all the instrumentation was connected to the service sources.

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1.4. LHC design flaws On 19 September 2008, just weeks before the LHC was first scheduled to start colliding protons, an electrical short caused massive damage. A connection between two superconducting cables developed a small amount of resistance, which warmed the connection (bus bar splices) until the cables — cooled by liquid helium to superconducting temperatures —lost their ability to carry current. Thousands of amps arced through the machine, blowing a hole in its side and releasing several tons of liquid helium. The expanding helium gas created havoc, spewing soot into the machine's ultraclean beam line and ripping magnets from their stands. Repairs took more than a year, and the LHC successfully restarted last November 2009. An investigation revealed that technicians had not properly soldered the cables together. With tens of thousands of such connections, it is perhaps inevitable that some were faulty, but design flaws worsened the problem. The silver–tin solder that was used melted at high temperatures and did not flow easily into the cable joints. Moreover, workers did not adequately check to see if each connection was electrically secure. Sensors to detect an overheating circuit, which might have helped prevent the accident, were not installed until after it happened. In addition when the wires were originally joined, the same silver–tin solder was used to connect them to an adjacent copper stabiliser, meant to provide an escape route for current in the event of a failure. That step risked reheating and destroying the original connection. Making the second connection to the stabiliser with a different type of solder that had a lower melting point could have avoided the problem. Such solution was considered and rejected because the alternative solder contained lead, a hazard to workers. Figure 1.9 shows a typical bus bar splice.

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Figure 1.9: Bus bar splices In a paper published by Rossi (2010), there is the conclusion that the catastrophic failure of a splice between two magnets was not a freak accident but the result of poor design and lack of quality assurance and diagnostics.

1.5. Conclusion

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In spite of flaws, the LHC project has been an important driving force for Innovation in European Industry.

Bibliography 1. Evans L. (Ed.) (2009), The Large Hadron Collider: A Marvel of Technology, CERN and EPFL Press 2. Rossi L. (2010), Superconductivity: its role, its success and its setbacks in the Large Hadron Collider of CERN, Superconductor Science and Technology, 23, 034001

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Topics for discussion and self-study1 1. Make inventory of the main concepts and their coupling and interactions with the larger context outlined in this case study. As starting point you may use and revise/ correct/ elaborate the following visual transcript (also magnified into full-sized segments at the end of this section). mission develop new technologies

train: scientists and engineers of tomorrow

large-scale computing (grid)

accelerators

reuse previous accelerators as first stages

gain knowledge: push back the frontiers of science

Large Hadron Collider

detectors

technical challenges beyond state of art

multiscale

accuracy cooling (cryogenic)

particle nano/ micro

mega (infrastructure)

macro (equipment)

Engineering Report Quality Assurance Manual

cost wishes/ constraints

size/ weight

scale

2 in 1 concept in magnet dipoles design modelling testing & validation dipole magnets micron precision magnetic collars redesign

coordination of suppliers

logistics

mass-produced

installation

storage

determine

event topology

nature of particles

energy of particles

solutions

corrective actions

operational deployment

cause 14TeV impacts to isolate particles for the purpose of detection

beam interaction points

couplings reuse of LEP modelling complexity experiment onion-like solutions detector concept

quality assurance

CERN as general contractor

reuse of cavern infrastructure

Atlas detector CMS detector

risk analysis failures

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dipole tractor

cryogenic cooling system

Then transform the transcript into an idea network to eliminate redundancies and identify and formalise unique idea relationships, as shown below.

1

The schematics in this section make use of ‘synaptic networks’ notation explained in Appendix 3.

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Barone M. Advanced engineering design as practiced today

mission train scientists and engineers of tomorrow

develop new technologies

reuse of cavern infrastructure acceleprevious rators accelerators Large Hadron reuse previous Collider accelerators as

cost wishes/ opportunities/ constraints

gain knowledge: push back the frontiers of science

large-scale computing (grid)

detectors cause 14TeV impacts to isolate particles for the purpose of detection and analysis

first stages technical challenges beyond state of art

beam interaction points

cooling (cryogenic)

multiscale

particle

accuracy modelling

energy of particles

inspiration, validation

things to nature of determine particles reuse of LEP experiment onion-like event detector concept topology

couplings nano/ micro

mega (infrastructure)

solutions

size/ weight macro (equipment)

Engineering Report Quality Assurance Manual

complexity 2 in 1 concept in magnet dipoles design

large project scale

CMS detector

testing & validation

dipole magnets

Atlas detector

micron precision magnetic collars redesign

quality assurance massproduced coordination of suppliers

logistics

CERN as general contractor storage

installation

corrective actions

operational deployment

risk analysis failures

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dipole tractor

cryogenic cooling system

2. What are the main relations and causalities that connect the items identified in question 1? How are they translated into processes and how effective are they? 3. Map the processes and challenges outlined in this case study onto two other case studies of your choice (also from this volume) and compare them. What conclusions do you draw? What advice can you give?

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Barone M. Advanced engineering design as practiced today

mission develop new technologies

train: scientists and engineers of tomorrow

large-scale computing (grid)

accelerators

reuse previous accelerators as first stages

gain know push bac frontier scien

Large Hadron Collider

detectors

technical challenges beyond state of art

multiscale

accuracy cooling (cryogenic)

particle nano/ micro

mega (infrastructure)

macro (equipment)

Engineering Report Quality Assurance Manual

cost wishes/ constraints

couplings reuse of modelling complexity experiment o solutions detector c

quality assurance size/ weight

scale

2 in 1 concept in magnet dipoles design mod testing & validation dipole magnets micron precision magnetic collars redesi

coordination of suppliers

logistics

mass-produced

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CERN as general contractor

reuse of cavern infrastructure

installation

storage

operational deployment

dipole tractor

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Barone M. Advanced engineering design as practiced today

gain knowledge: push back the frontiers of science

ge-scale mputing (grid)

cost wishes/ constraints ing

beam interaction points

reuse of LEP experiment onion-like detector concept

corrective actions

operational deployment

nature of particles

energy of particles

solutions

redesign

stallation

e

determine

event topology

ign modelling testing & validation cision ollars

cause 14TeV impacts to isolate particles for the purpose of detection

Atlas detector CMS detector

risk

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

analysis failures

dipole tractor

cryogenic cooling system

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Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved. doi:10.3233/978-1-61499-242-4-23

2. An innovative system for vessels monitoring, diagnosis and prognosis, and the challenges to be faced Katsikas S. (Serafeim) Director of Research and Development, Prisma Electronics SA, Alexandroupolis, Greece; www.prismaelectronics.eu

Summary This chapter presents a part of the experience during the effort in Prisma Electronics to design and develop an innovative system for vessel monitoring, diagnosis and prognosis. The process of product development is shown to be driven from the market and the technological background of the company, and the important role of clear vision and effective communication is illustrated.

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2.1. Introduction Prisma Electronics SA was established in 1992. Based in Greece, we provide services and products in information technology, in the electronic fields. We are dedicating to offer high quality services in developing innovating products. That presupposes a well organised R&D department and of course the company culture that support and encounter the creativity and the innovation. In our facilities we have an assembly line for surface mount and the Through-hole electronically bonnets and instruments for optical, electrical and operational test. The base of Prisma is in Alexandroupolis and we have a branch in Athens and an office in New York in the United States. CERN awarded our company as Gold Industrial Partner for our exceptional services during 2009. In the last six years one of our basic research activities has been in the fields of wireless sensors networks. For more than two year we have developed a hardware and software platform to support applications based on smart wireless

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

sensors. Our platform is used in other European technical universities and institutes, but our business target was not to provide a development platform. We aim to develop systems with smart sensors for specific applications.

2.2. Business model

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We came across a big dilemma. In which of the fields, where the smart sensors could be applied, should we focus? Industrial automation, meteorology, space, buildings, management, defence, agricultural, transportation, condition based maintenance, production, medical and energy are only some of the fields where smart sensors networks are going to be widely used in the next years. Let us see some of the basic factors to take a decision. The first factor is your business model. It is not easy to make big changes in your business model. So if you have an innovative idea you must find a field that is very close to your business model. Also, it is much easier and less time consuming if you start to develop your product for a familiar market and application. Also very important is a basic market analyses in order to evaluate your possibilities at the time for you to get a good market share and financing. You must find out your potential competition in each field. The absence of competitors in the marker field is not necessarily a good thing, or the whole market is not mature or your idea has not got any added value to your costumers. Another very critical factor for your decision is your relations or at least the ability to create a relation with potential customers who have the capability and the will to provide information about their needs and try new methods and products. The last one I believe that is the most important in order to take a decision how to use your knowledge.

Figure 2.1: Business model.

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

Figure 2.2: Customers allocation according to their receptivity to new technologies and methods. In this diagram you can see the allocation of the customers according to their receptivity to new technologies and methods. If your product is unique and innovative, then you have to find out the small group of potential customers over there. As technology enthusiast they will partially invest in your product as a solution to their needs. This could be your collaborators to retrieve useful information and make a pilot installation to prove your concept and finalise your product. The next category is the visionaries and after that there is a chasm. The next one is the pragmatists that you have to persuade and prove them the added value of your product to their business. After that you have the conservative and at last you have the sceptics who are going to buy your product because it will be imperative.

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2.3. Problem identification and market study Problem description Let us go back to Prisma’s dilemma. In Greece, despite our financial crisis, we have a very strong industry. Greek maritime companies own almost twenty per cent of the global cargo fleets capacity. There are a great number of companies with dry-bulks and container ships. Also there are a lot of companies that offer services and products to maritime companies and we have universities and technical institutes with knowledge and expertise in this field. It was obvious for us as a first choice to find out if a system based on smart sensors and

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

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wireless network sensors would have added value for maritime companies. Our first issue was the definition of the need. At the beginning we had to learn the basic rules of the maritime market and the culture of the companies. If you do not know the main characteristics of the market, you can easily destroy your name, your reputation and after that it is very difficult to get back to that market. We had to find out the whole structure and the procedures of the maritime company and this is exactly the key to know which person in which position is the right one to present your ideas. Then we had to define our strategy to approach the market to establish a communication channel without making any promises our without spreading out all our ideas. We get the feedback from a lot of people in different positions and organisations. Based on that feedback we tried to define the real customer space and describe our solution based on our knowledge. We presented our solution to a number of people who could give us factual and authoritative information and we repeated these steps again and again until we could support the added value of our product. During that processing we searched for information on the internet, in bibliography and we purchased market reports, we attended relevant conferences and exhibitions, we became member of associations, we participated in R&D projects, we made collaborations with technical institutes and other companies, we tried to get feedback through our market, friends in technical groups in internet social networks. Beside all of these actions, the most critical information was provided by engineers and technicians in maritime companies who described clearly their need and evaluated our proposal. Proposed solution I shortly present you the results of this process, the real need in the maritime companies that we have defined (Figure 2.3).

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

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Figure 2.3: Structure of maritime companies. Here is a typical structure of a company. In the headquarters there is a general manager and all report to him. The operational manager is responsible for the operational schedule of the ships and the technical manager who is responsible for the operational condition of the ships, the maintenance schedules and new constructions. Depending on the number of the ships, the fleet is organised into groups of five to ten ships maybe even more. For each group there is a fleet manager with his technical team. That person coordinates the execution of the scheduled tasks, observes the operational ships’ condition and is responsible for solving any technical and operational problems. Let us see the information flow diagram. We have the fleet manager, we have the captain and the technicians on board and we have the engineering team that support the fleet manager. The fleet manager bases his own decisions only on the reports that he receives from the ship technicians, through the captain by an e-mail. This is exactly the problem.

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

Figure 2.4: The information flow diagram during a scheduled inspection or an alarm.

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First of all, the inspections are scheduled and there are not any realtime data. Always there is the human factor inside the reports. Here in this point we have an indirect report and so the problem description is not always accurate. The problem is that we have to take a decision not based on actual real-time data.

Figure 2.5: Problem of the existing maintenance system. The main disadvantage of that model is that you do not have any control, for example, on fuel and oil consumption. That means that it is very difficult to establish a common policy to reduce fuel and oil consumption in the ships. The second one is that they are based, even today, on schedule maintenance and they cannot make the transition to condition based maintenance, so there is high cost on assets and 28

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

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maintenance. They are unable to validate the technical reports. There are limited and unreliable technical data and it is also difficult the evaluation of the crew. There are a lot of difficulties on fault or alarm diagnoses. The costs in order to repair are very high. There is not any prognoses system, because there are not real-time data, so it is unable to prevent breakdowns of the ships. They are depending only on the experience of their technical staff. There are no real-time measurement of the exhaust and the environmental effects so they are actually unable to comply with the environmental regulation. During the next year there are going to be more and more of these regulations. Another task was the evaluation of the added value of our solution by estimating the impact on the operational cost of the ships. With our proposed system we are aiming to reduce the operational costs of the ships which are based on repairs, maintenance, low boils, fuel expenses and communication expenses. The other costs are the salaries of the crew, the insurances, stores port fees etc. Market Estimation Based on statistical analyses of the operational cost, we estimated the size of the potential market and the possible added value of the system. By focusing on the Greek, Japanese and north-European market, which is almost equal to half of the global market, the size of this market is about eleven billion dollars per year. Based on our products we can implement a system, which has been proved to reduce about five per cent the operational costs. This means a cost reduction about forty thousand dollars per year per ship for the maritime company. By implementing prognosis and diagnosis data analysis algorithms in our system, the cost reduction could be increased to twenty five per cent, which corresponds to more than one hundred thousand dollars costs reduction per ship. In this estimation are not included the prevention of any breakdowns, control of the fuel consumption, etc.

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Figure 2.6: Saving cost diagram. After the market bottom up and top down analysis, we had to make a list of basic guide lines or principles that we should follow during the developing of the products. A fact is that the maritime market is a quite closed market where it is difficult to be accepted. We should be very careful about what we promise and what we really can deliver to our clients. Also in the vessels there are environmental conditions that are aggressive for any electronic device. We had to consider this during design. We simulated these conditions and tested every electronic circuit that we had to embed in our system. Also, the standards in the maritime industry are very high and there are restrictive specifications for anything that is installed in the vessel. Especially for a new system it is very difficult to install something that is not qualified and approved. Every new system must be adapted to their methods and processes. It would be very hard for a system to be acceptable if the maritime company had to change the processes. Also some software tools and systems are commonly used in this market so we had to interconnect our system to these tools. Another fact is that any installation in a ship is a very difficult task because the ships travel all over the world. So everything in our system should be parameterised and remotely reconfigurable. Even the embedded devices should be remotely programmed. The solution should be easily adaptable to any type of vessel. That is why our systems had to be independent of the

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ship’s control system and with as little as possible mechanical modifications. At last, the solution should be easily and with low cost expandable.

2.4. The concept of Laros

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So based on these facts, we came up with the specifications and the description of the system. The name of it is Laros, which means seagull in ancient Greek. Laros is a monitoring system based on a wireless smart sensors network for continuously monitoring and estimating factors that indicate the status and the condition of critical assets in the ships. Most of the sensors are wireless in order for the system to be installed quickly with low costs and easily expandable at any time. The smart sensors are taking real-time measurements of physical parameters like temperature, pressure, liquid level, vibration and consumptions, estimate the status of the assets based on pattern recognition algorithms for novel detections and transmit the results wirelessly to the server on board. The server sends the report and the alarms to the headquarters through the satellite links. So Laros is a software and hardware platform. It is a tool. It is totally configurable, expandable and adaptable to any vessel type and operational demand.

Figure 2.7: Electronic system configuration. The next issue was the description of the system architecture. We defined the system requirements, the modules of the system, the

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architecture and the requirements of each module and we described all the interconnections between the modules. In the ships there are the sensors which are connected to the collector devices with embedded software for signal analysis and novelty detection. The collectors are connected to a wireless network inside the ship. Through a gateway, all the data are stored in a server in the ship. Also, the server analyses the data and produces diagnosis and prognosis results. Through a satellite communication link the system transmits reports to the datacentre of the headquarters, or raw measurements after demand. In the datacentre we have software for visualization of the data and statistical analysis. Different types of sensors are connected to the collectors. The sensors’ interfaces could be serial, analogue or based on frequencies, current or voltage.

2.5. Electronics system

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First of all we have to think about the sensors and this was a key question. Which of the physical quantities must be measured in order to make a diagnosis and prognosis of the vessels’ critical assets? Which is the required limits accuracy, resolution of each measured quantity? And which types of sensor of each measurements point meets the environmental requirements? Is the power consumption low? Does it require less mechanical modification to be installed? These were the basic questions in order to decide which type of sensor we should use in order to measure the quantities.

Figure 2.8: Need for electrical equipment to control of engine.

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

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This is a typical picture of an engine in a ship. The first basic things that we had to measure were the flow of the oil, the gas temperature, the water temperature, the fuel flow inside the machine, the bowl of the generators, the vibration on the shaft, the torque of the engine and the speed of engine. We had to test a lot of different types of sensors. We used ultra-sonic, organic sensors, mechanical sensors, different MEMS sensors, optical sensors and acoustic sensors. Also, for all the sensors we had to design the necessary electronic parts in order to try to connect them to our board. In the collectors which encapsulate most of the innovation of the project, are small embed electronic devices capable to receive and manipulate measurements from different types of sensors. Also, this can be powered autonomously based on batteries or energy harvesting and capable to connect it to a wireless network. Actually the collectors have all the characteristics of small smart transducers. By overcoming the limitation of the wires, we reduced by fifty per cent the installation cost and eighty per cent the installation time. The system is independent of the control system, and easily adaptable to any vessel type. The collectors’ network is easily expandable at any time. There is no actual limitation to the number of the connectors and the network can be expanded by adding routers and gateways. The embedded devices are remotely configurable and controlled. Also, we have implemented self-learning algorithms in some application cases to eliminate the parameterization need.

Figure 2.9: Wireless Network Diagram.

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

The wireless communication inside a ship was another challenge that we faces. A ship is made of thousands of tons of metal and our main consideration was the range and the reliability of the wireless network. We made simulations and field tests with different types of wireless protocol. The basic evaluation factors were the reliability, the security, the interoperability and the low power consumption. The performance of the communication based on IEEE standard 80215.4 was outstanding as by adjusting the transmission power, we managed to cover the entire engine room and send data to the bridge using only one router on the first deck. Also, in order to have interoperability and security we chose the ZigBee protocol and the standard of IEEE 1451.5 for the collectors interface.

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2.6. Energy harvesting Another challenge was the energy harvesting. We tested different types of energy harvesting like micro generators in order to have energy from a vibration or movements. We tested photovoltaic for sensors that would be installed outside the engine room. Also we tested thermo electrics and of course batteries. Additionally we took all the considerations during the design of the electronics, in order to reduce the power consumption of the collectors. In order to build a system which is easily adaptable, we made a lot of improvements and upgrades to our operating system for the collectors. We designed two types of collectors, one based on microcontroller and one based on DSP for more demanding signal analysis applications like vibration and acoustics analysis etc. With our operating system we manage to reduce the power consumption, increase the communication interoperability, improve the adaptation of the system and significantly reduced the time to develop a new application. Also we added other features like the synchronisation of the real-time clock of the collectors. We added a function for measurements simulation so you can simulate a fault situation and observe the systems’ reaction. We added frequency agility which means that if there is interference in our wireless communication channel, it will be detected and the coordinator will select another channel. The system is quite complicated and we had a lot of other tasks like mechanical designs of the enclosures, developing server side software, databases, communication protocols, novelty detection algorithms, statistical analysis, web based application for data presentation, interfaces to ERPs and SCADA tools etc.

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

2.7. Collaboration The whole project to be developed in-house by a small company is very hard to be successful. It was necessary to create a strong collaboration with other companies and technical institutes. Also we had to create a good strategic business plan. The first thing was the scaling of the technical fields according to the importance. We had to decide which of the modules and subsystems should be developed inhouse. We created the working groups, recruited new staff, and we collaborated with technical institutes and cooperated with other companies. We built an operational plan. We had to set clear goals and priorities, build the action plans, trade of between short term objectives and long term goals, establish evaluation process to make sure people will meet their commitments and we had to implement communication rules and tools. Documentation of everything was very important in order to create a vision and share it with our people. This is the most important of all, to have a clear vision. To make your people believe it.

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In any engineering design project, important steps must be to: x Set clear goals and priorities x Develop the action plans. Trade-off between short-term objectives and long-term goals x Establish follow-through measures to make sure people are meeting their commitments x Use communication tools like SharePoint, UML etc. x Define communication rules x Document everything x Create a vision and share it with your people The creative team of Laros is quite big enough. It is not just Prisma. In Prisma we have a coordinator team, we have a hardware design team, an embedded design team, RF design, wireless sensors networks, optical sensors, R&D department, production department, evaluation team, installation and field measurement team. Also, we created a spinout company with the title of MDP in order for the basic members of these teams to participate to the vision. Additionally we have a number of sub-contractors for condition based algorithms, novelty detection, fuzzy logic and mechanical designing. We have a very good collaboration with technical institutes like the optical sensor department of the National Hellenic 35

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

Research Foundation, the special department of micro generators of NCSR Democritos, and the Universities of Nancy, Thessaloniki, Thessaly and Xanthi. We collaborated with companies like ERP companies for maritime, communication tools, companies specialised in energy harvesting, embedded software and design of MEMS. Also, we are participating in European research projects in order to support the development of LAROS.

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Lastly, I would like to give you our point of view about the meaning of the advanced engineering. Someone forward me a very clever sketch which visualises the usual road map of a project:

How the customer explained it

How the project leader understood it

How the analyst designed it

How the team designed it

How the project was documented

How the Business Consultant described it

What was really developed

What the customer was billed

How it was supported

What the customer really needed

Figure 2.10: Road map of a project (reproduced from projectcartoon.com).

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

What is advanced engineering? It is when we have the same image of the developing system in all the project phases.

How the customer explained it

How the project leader understood it

How the analyst designed it

How the team designed it

How the project was documented

How the Business Consultant described it

What was really developed

What the customer was billed

How it was supported

What the customer really needed

Figure 2.11: Ideal project roadmap

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

Topics for discussion and self-study 1. Make inventory of the main concepts and their coupling and interactions with the larger context outlined in this case study. As starting point you may use and revise/ correct/ elaborate the following visual transcript (also magnified into full-sized segments at the end of this section).

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

current own business model information

potential customers

acc market analysis

define

where to focus development?

feedback

‘Laros’ system

expandable

module requirements

cause s prob lems (effe cts)

validation of technical reports

prognosis

evaluation of the problem

modules

system quirements requirements

solutio ns

fault/ alarm diagnosis alarms

module architecture

ability to comply with environmental regulations

scheduled inspections

couplings

adaptable

maintenance

information flow

system architecture

configurable

requirements realtime mon itorin glo g in form bal ation flow operation

(ill-) effects on

enabling technologies

economical value

not easily defensible?

strategy of approaching

software

ds ee n :n us esig foc e d iv r d

main aim

solution

get

serv r ices services

mission

ma co nag mp ing lleex ity

n ar le

analyse

structurres and structures procedurres of the procedures potential customers

fleet management organisation

definition of architecture

constraints

lea learn arn

rules of the market sources of information

products

lop

target market: maritime definition of a need

conservatives

visionaries

competition

ve

skeptics

pragmatists

technology enthusiasts

electronic systems

geoeconomical criteria

mainstream

de

potential customers early market

wireless sensor platforms

decisionmaking factors

ess

participate in pilot project

established field of expertise

interconnections

choice drivers

problems

perf rformance performance & reliability

human factor

regulations

easy adaptability

indirect reporting

team structure

scale technical fields (importance) operational plan clear goals & priorities

communication

create & share vision with team follow-through tools measures: ensure people document are meeting their everything commitments long term goals (sharepoints, UML etc)

action plans

technical institutes

decide scope of in-house development

rules

other companies (cooperation well-defined)

working groups

trade off short term objectives

recruit

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

Then transform the transcript into an idea network to eliminate redundancies and identify and formalise unique idea relationships, as shown below.

38

Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis current own business model

give information access to potential customers participate in pilot project potential technology customers enthusiasts early market

established field of expertise

market analysis geoeconomical criteria

mainstream

visionaries

wireless sensor decisionplatforms making factors electronic focus: needs systems drive design competition

skeptics

pragmatists

where to focus products development?

conservatives target market: maritime definition of a need

rules of the market sources of information

structures and procedures of the potential customers fleet management organisation

get and analyse feedback

information flow

not easily defensible?

economical value ‘Laros’ system

globa

l info rmat ion flow

maintenance validation of operation technical reports

alarms scheduled inspections

system

real-t monit ime oring

define strategy of approaching

evaluation of the problem problems

software

services

solution

learn

mission

develop

(ill-) effects on

fault/ alarm diagnosis

ability to comply with environmental regulations

solut

ions

cause s proble ms

(effec

ts)

prognosis

human factor

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

indirect reporting

39

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Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

2. What are the main relations and causalities that connect the items identified in question 1? How are they translated into processes and how effective are they? 3. Map the processes and challenges outlined in this case study onto two other case studies of your choice (also from this volume) and compare them. What conclusions do you draw? What advice can you give?

40

Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

current own business model information

potential customers

decisionmaking factors

a cc

e ss

participate in pilot project

market analysis

potential customers

geoeconomical criteria

mainstream

early market

skeptics

pragmatists

technology enthusiasts

target market: maritime definition of a need

conservatives

rules of the market

n ar le

analyse

feedback

sources of information

define

structurres and structures procedur res of the procedures custo mers potential c customers

fleet management organisation

definition of architecture

wh de

constra

lea learn arn

visionaries

competition

solution ‘Laros’ system

not easily defensible?

requirem realtime mon itorin glo g in form bal ation operation

get strategy of approaching

maintenance

(ill-) effects on

validation of technical re

information flow

fault/ alarm diagnosis prognosis

evaluation of the problem

alarms

ability to comply with environmental regulations

scheduled inspections problems human factor indirect reporting

te

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

scale technical fields (importance) operational plan communication

clear goals & priorities action plans

rules

create & share vision with team

follow-through tools measures: ensure people document are meeting their everything commitments long term goals (sharepoints, UML etc)

trade off short term objectives

decide scope of develo

41

Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Katsikas S. An innovative system for vessels monitoring, diagnosis and prognosis

n del

established field of expertise wireless sensor platforms

decisionmaking factors

definition of architecture

where to focus development?

constraints

lop

products

ve

competition

mission

de

electronic systems

software

serv r ices services

s ed ne n s: esig u foc ve d dri

enabling technologies

system architecture

main aim

‘Laros’ system

modules

configurable

requirements realtime mon itorin glo g in form bal ation flow on

expandable

couplings

ma co nag mp ing lex ity

economical value

system quirements requirements

adaptable

soluti

ntenance

caus

lidation of technical reports

prob

/ alarm diagnosis

ons module architecture

es

lems

osis

module requirements

(effe

interconnections

cts)

comply with tal regulations

choice drivers perf rformance performance & reliability

regulations

easy adaptability team structure

ale technical fields (importance)

technical institutes

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

decide scope of in-house development eate & e vision h team

other companies (cooperation well-defined)

working groups recruit

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Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved. doi:10.3233/978-1-61499-242-4-43

3. Future challenges for road transport Editorial2

Summary

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

The presentation showed how DAF trucks conducts its development process in parallel through technology projects and shorter term product development projects receiving input from the technology projects. Ideas funnel through stage-gates into roadmaps anticipating important trends for the coming decade, and finally technology projects are selected based on the identification and prioritisation of the most critical aspects and initiated. Drivers for product development in the project definition phase are the general requirements for performance improvement and cost reduction, as well as other aspects contributing to the program of wishes. Through stage-gate management, project definition is succeeded by the concept phase, the engineering phase and the volume validation phase.

2

Based on the oral presentation by Martens J. (Jack), DAF Trucks NV

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Editorial Future challenges for road transport

Visual transcript of the presentation (also magnified into full-sized segments at the end of this section).

prioritise/ focus

bigges

t cont

ribut

ion to

prob

lem

identify critical aspects system decomposition evaluation phase

powertrain & energy management

parametric investigations

demonstrators volume validation small series phase production validation

market introduction

development of methods & tools

transport efficiency vehicle safety

challenging aspects

driver comfort

connectivity

technology predevelopment

noise

modelling elling & virtual prototyping ototyping

evaluation e valuation of concepts conc cepts

stage e gate manag gement management concept phase

define product description: key choices

project selection

vision, mission

optimisa ation optimisation of design de esign

long term planning

strategy

detailed designs made

technologies

portfolio management

choice e of market introdu uction date engineering introduction phase

project pipeline

gateway review & project management

uncertainty of predictions investments, tooling

continuous monitoring of developments

criteria

proj o ect start project

product development dept

s: wishe nge gss ng challe meetin scrum

program of wishes

important trends for coming decade

definition phase roadmaps

marketing & sales dept

stage gate management

type of product, specs, look & feel general requirements

evelo uct d prod

nt pro p me

reduce cost

jects ideas

g nolo tech

y pro

jects

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improve performance

44

Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Editorial Future challenges for road transport

bigge

st

evaluation phase

demonstrators volume validation small series phase production validation

gateway review & project management

investments, tooling

market introduction

e of market choice introdu uction date engineering introduction phase

detailed designs made optimisa ation optimisation of de esign design

modelling elling & virtual ototyping prototyping

stage e gate manag gement management concept phase

define product description: key choices

evaluation e valuation of concepts conc cepts

p roj o ect start project

product development dept

es: wish enge etings chall me m scru

program of wishes

definition phase

type of product, specs, look & feel

marketing & sales dept

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general requirements

prod

u

velo ct de

pme

nt pr

ojec

reduce cost improve performance

45

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ts

Editorial Future challenges for road transport

prioritise/ focus

bigge

st co

ntrib

ution

to pro

blem

identify critical aspects system decomposition

powertrain & energy management

parametric investigations

demonstrators

transport efficiency

development of methods & tools

vehicle safety

challenging aspects

driver comfort

connectivity

technology predevelopment

noise

project selection

vision, mission

strategy

portfolio management

t

long term planning

technologies

project pipeline

gateway review & project management

uncertainty of predictions

continuous monitoring of developments

criteria

roj o ect start roject

important trends for coming decade roadmaps stage gate management

ts

rojec

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

duct

ost

lop deve

tp men

ideas

no tech

logy

proje

cts

46

Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved. doi:10.3233/978-1-61499-242-4-47

4. Tolerances optimisation in the mechanical design of components for a medical Linac Garlasché M. (Marco) Project Engineer, ADAM SA, Geneva, adam-geneva.com

Summary This chapter focuses on the analysis performed by ADAM SA3 mechanical department in order to optimise the production of components for the Linac for Image Guided Hadron Therapy (LIGHT), a linear accelerator dedicated to cancer treatment. After a brief introduction on proton therapy and on LIGHT, the case study is presented4. Essential basic theoretical background on accelerating cavities and production tolerances drives the analysis of tolerances, followed by the numerical evaluation. The main design goal is to maintain the performance accuracy under more relaxed manufacturing tolerances.

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

4.1. Introduction to proton therapy Proton therapy is a medical radiation treatment which takes full advantage of the specific characteristic of a beam of protons for damaging the cancerous cells of a tumour. As opposed to X-rays (used in conventional radiotherapy), the protons’ depth-dose profiles5 show a low energy deposition at the entrance in matter, which then increases at a certain depth, just before the proton stops (Figure 4.1 left): this is the so called Bragg peak (Wilson, 1946) (Figure 4.1 right). The depth of this peak is function 3

ADAM: Application of Detectors and Accelerators to Medicine Refer to chapter ’Mechanical Optimisation of a RF Coupling System for a Medical Linac through FMEA’ for further information both on LIGHT and on proton therapy. 5 The depth-dose profile represents the profile of the energy released by ions inside traversed matter. 4

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Garlasché M. Tolerances optimisation in the mechanical design of components

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

of the proton’s energy before entering the target and can be varied by acting on the acceleration system. Furthermore, thanks to its charged nature, a beam of protons can be guided transversally using magnetic fields. Due to these main features (i.e. reduced energy deposition at entrance, longitudinal and transversal Bragg peak positioning) protons are considered quantitatively better than X-rays. They allow, in fact, for a better conformation of the dose (Figure 4.2) by delivering the maximum energy to the tumour while sparing the healthy tissues around it. Due to these main features (i.e. reduced energy deposition at entrance, longitudinal and transversal Bragg peak positioning) protons are considered quantitatively better than X-rays. They allow, in fact, for a better conformation of the dose (Figure 4.2) by delivering the maximum energy to the tumour while sparing the healthy tissues around it.

Figure 4.1: Left: The photon beam passes through the tumour target leaving energy in the tissues before and after it; on the contrary, the proton beam stops at a certain depth, which is related to its initial energy. Right: The depth-dose profile of protons vs. photons: compared to photons, for the same value at a desired depth, protons give down to 10% of dose to shallow healthy tissues (PSI, 2008)

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Garlasché M. Tolerances optimisation in the mechanical design of components

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Figure 4.2: The treatment plan with photons (left) and protons (right) for a tumour (dark middle zone) in the head region: irradiation by photons generates a dose bath in a large part of the brain, also affecting critical healthy tissues. This can be avoided by using proton therapy (PSI, 2008). Even though the first medical treatment with protons dates back to 1954 (performed at the Lawrence Berkeley Laboratory, USA) proton therapy has doubtlessly flourished in the last 20 years, when acceleration systems and imaging technology breakthroughs allowed for the full exploitation of its potential. Still, the high investment costs and the machines size prevented the spread of proton therapy centres if compared to the diffusion of radiotherapy. Nevertheless, it is expected that in ten years, for every 10 million inhabitants, about 20000 patients per year will be treated with conventional radiotherapy, whereas at least 12% of them would benefit of a better treatment if proton therapy would be available (Amaldi, 2010).

4.2. LIGHT In answer to this need, ADAM’s aim is to offer a turnkey system which features innovative treatment capabilities and is economical enough to be attractive to the market. The heart of such treatment centre is a proton linear accelerator (Linac) called LIGHT (Linac for Image Guided Hadron Therapy).

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Garlasché M. Tolerances optimisation in the mechanical design of components

Figure 4.3: Draft view of how the entire system could look like. The low-energy particle acceleration (up to 30 MeV) is performed by a cyclotron, while the main acceleration (up to 250 MeV) is given by LIGHT. The Linac itself is composed of many modular units, each powered by an independent source (called Klystron, on top). Concerning the need for enhanced treatment capabilities, among all conventional accelerators the Linac is the one which can best exploit the features of proton beams. Thanks to its modularity, in fact, it is possible to actively vary the longitudinal position of the Bragg peak during treatment (Table 4.1) just by switching on and off part of the Linac units. This allows for 3D positioning of the beam during treatment, thus for multiple “painting” of the tumour volume and for the treatment of moving organs.

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Table 4.1: Comparison of beam energy variation typology and timing Accelerator

Beam always present (@ treatment)

Energy variation

Time needed for variation

Cyclotron

Yes

Mechanical

80-100ms

Synchrotron

No

Electronic

1s

Linac

Yes

Electronic

1-2ms

i) a Linac can vary energy electronically in a few milliseconds by switching on and off its units; ii) a synchrotron varies energy electronically by reducing the acceleration steps but can do it only on a new train of protons and needs seconds for varying the field of its magnets; iii) a cyclotron varies energy in tens of milliseconds by degrading beam via mechanically operated collimators. 50

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Garlasché M. Tolerances optimisation in the mechanical design of components

Furthermore, the modularity of the structure is also economically very attractive because it: i) allows for a wider range of possible centre configurations, from simpler systems (1:2 accelerating units) able to treat shallow seated tumours (1 to 4 cm depth), to more complete ones (10 accelerating units) able to treat deep-seated tumours (up to 30 cm depth); ii) extends to the subcomponents of each unit, thus granting easier industrialization of production and lower costs. Being it the core element of ADAM entrance product in the market, one can understand the importance held by LIGHT. Therefore, in 2007, the company decided to build a prototype of this Linac and, due to the system’s features, a one unit configuration was chosen (called ‘First Unit’). Such prototype helped to address two main challenges: i) as a start-up and CERN spin-off company, ADAM had to prove the feasibility of the production of an accelerating structure in a completely industrial context; ii) the prototype production represented the ‘battlefield’ for debugging and optimising all design and manufacturing steps, especially in order to minimise the overall costs.

4.3. The First Unit and its components

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The case analysis reported deals with one of the manufacturing optimisation studies performed after the First Unit production; namely it redefines the procedure for the specification of tolerance requirements for the so called half cells, the basic component of the Linac.

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Garlasché M. Tolerances optimisation in the mechanical design of components

A

B

C

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Figure 4.4: The Linac modular element called First Unit: A) the Klystron together with its electronic equipment, B) the RF line, C) the accelerating unit on its support. Figure 4.4 depicts the First Unit: a Klystron (a) supplies the radio frequency (RF) power, which is then delivered through the RF line (b) to the Linac (c). The power is then split in the four accelerating blocks, which need it in order to accelerate the proton beam along the axis (Figure 4.5).

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Garlasché M. Tolerances optimisation in the mechanical design of components

Figure 4.5: Section view of the First Unit accelerating system, the proton beam is being accelerated while passing through the axial bore.

Copyright © 2013. IOS Press, Incorporated. All rights reserved.

Every block is in turn composed of equal accelerating subunits, which are called cells (Figure 4.6) and are considered the basic element for radiofrequency. For what concerns the assembly, every cell is actually composed of two equal elements called half cells, which are made of OFE copper and are asymmetrically brazed together to form the cell. They are considered the basic mechanical element and the production of 1280 pieces is foreseen for the complete version of LIGHT.

Figure 4.6: Centre: View of the two sides of a half cell. Two half cells are brazed together in order to obtain a cell. Left: Section view of a cell. Right: 2D view of a section of a half cell with profile

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Garlasché M. Tolerances optimisation in the mechanical design of components

tolerance specification, notice the typical nose-like features near the axis hole for enhancing the max E-field. As will be explained in Section 4.4, the precise manufacturing of the half cells is crucial for the Linac to work properly; this leads to a tight tolerance specification of the half cells profile (Figure 4.6 right). On the other hand, such tolerances should be kept as relaxed as possible due to economic considerations. Therefore, ADAM mechanical dept. had to revisit the cavity design procedure in order to reduce production costs while maintaining the required quality of the product.

4.4. Basic theory for cell design and production The optimisation of the half cells design and production requires a multidisciplinary approach, stretching from the field of RF engineering to the one of design for production. In the following the needed theory on both fields will be briefly presented.

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Radiofrequency of a cell An accelerating cell is a hollow space with specific metallic boundaries such that selected electromagnetic waves can oscillate inside it at selected frequencies, thus accelerating particles by means of the time-varying electric field along the axis. The basic structure which is interesting for acceleration is the pillbox cavity. As can be seen in Figure 4.6 (left), this simple cylindrical shape excites a particular electromagnetic waves mode, called TM010, which has the maximum amplitude of the electric wave on the axis and is therefore the most efficient for particle acceleration. Through its electrical equivalent, the pillbox cavity can be modelled as a lumped circuit oscillator where the oscillation frequency f is proportional to the inductive (L) and capacitive (C) parameters,

fv

1 LC

while L and C are in turn proportional to the inverse of the diameter and the volume of the cell respectively:

Cv

1 , L v Vcell dcell

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Garlasché M. Tolerances optimisation in the mechanical design of components

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Figure 4.7. Left: The cylindrical shape of a pillbox cavity excites the TM010 mode with maximum longitudinal electric field (Ez) on the axis. Right: Section view of First Unit cell with equipotential lines of the excited electric field Even with the presence of some geometrical variations for enhancing efficiency, the First Unit cells follow similar frequency-geometry relationships. The frequency of every single cell (therefore, as seen, its geometry) is important because of two main reasons: a) Cavities bunch synchronisation: the cells frequencies must stay within a small interval one to the other in order to be synchronised with each other and with the beam of protons passing by; b) Frequency constraints of the power sources: cells also need to be synchronised with power sources, whereas Klystrons possess a steep power-frequency characteristic, in which the plateau of maximal power distribution covers a small frequency interval. In the case of the First Unit (resonating frequency at 3 GHz), if no workaround solutions were implemented, the precision needed for the half-cell profile would settle around a 10μm band. The common way to bypass this constraint is to tune the cells. Tuning is the technique with which the real volume of the cell, therefore the L/C ratio, is changed in order to make the cell resonate near the ideal frequency. The most efficient way to do it is through the insertion in the cell volume of lateral rods (Figure 4.8), which are then brazed to the half-cell outer walls. Still, the total inserted volume is constrained both by mechanical feasibility (i.e. maximum allowable hole diameter for insertion) and by radiofrequency (excessive number and length of the rods perturb the electromagnetic waves of the cell). Therefore, even though this technique greatly relaxes the precision

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Garlasché M. Tolerances optimisation in the mechanical design of components

requirements up to around a 30 μm band, some other action is advisable to further loosen tolerances.

Figure 4.8: Two copper rods are inserted laterally on a half-cell for tuning.

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Statistical tolerances and design for production A sensible specification of dimensional tolerances for manufacturing is a key element for increasing productivity (Chase, 1987). For what concerns production, in fact, the tighter the tolerances the higher the costs: tolerance requirements affect all levels of product manufacturing, from the selection of machines and tooling, to the operator’s skill level, the machining time (speeds and feeds may be reduced) and the precision of control.

Figure 4.9: Cost vs. Tolerance curves. Continuous: exponential (Speckart); Short dash: reciprocal squared (Spotts); Long dash: reciprocal (Chase & Greenwood).

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Garlasché M. Tolerances optimisation in the mechanical design of components

In the years some effort has been put in order to obtain significant cost vs. tolerance curves. In Figure 4.9 three of the most common models are reported. Both the reciprocal and the reciprocal squared laws for cost C follow a power function to the tolerance T B C A K T Where A represents the fixed costs, such as material, setup costs and tooling; B describes the cost of production for a single component; K represents the sensitivity of a given process to changes in the tolerance requirements. K equals 1 and 2 for the reciprocal and the reciprocal squared respectively. Speckart, instead, gives the exponential relation:

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cost

A  BeCT

where coefficients B and C both account for single component production and sensitivity. Such curves can give a good idea on the cost-tolerance relation and may be used for analyses. On the other hand, it has to be reminded that production characteristics are extremely site- and machine-dependent, therefore a thorough verification should be performed before applying these formulas to any single production. The specification can be defined in terms of two limits, the Lower Specification Limit (LSL) and Upper Specification Limit (USL). a) Once these specification limits for a product’s final acceptance are set, two philosophies may be followed for defining the manufacturing tolerance band. The first, and more conservative, is the Worst Case Output (WCO). As described by its name, this approach takes into consideration the worst case possible, by forcing the concept that the dimensional outputs of the produced parts won’t follow any particular distribution inside the tolerance band specified (and could for example all fall near the tolerance limits). b) On the other hand, STatistical Output (STO) takes into account the low probability of worst case occurrence by considering the dimensional outputs of the produced parts as following a statistical distribution. This approach is nearer to manufacturing reality: most of

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Garlasché M. Tolerances optimisation in the mechanical design of components

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the parts will in fact fall around a mean value, while only fewer and fewer will fall as the dimensional extremes are reached. Usually the statistical model used for describing this behaviour is the Normal distribution, centred on the mean value of the specified tolerance band (Figure 4.10) and with deviation σ (which defines the process capability, i.e. precision). USL  LSL μGauss μspec , Pspec. 2 It has to be reminded that the symmetrical positioning of the curve at the tolerance midpoint does not take into consideration eventual skewness or mean shifts due to single and recursive errors (e.g. tool wear, setup errors, and thermal deformations); this can cause a much higher ratio of defective products. Initial curve validation, if possible, plus good knowledge and constant monitoring of the process are therefore advisable. By making no assumptions on the production behaviour, WCO intrinsically demands that all pieces produced fall inside specification limits. Therefore, in the real world, a statistically6 behaving process will have to tighten its capability to meet this need, so that 100% of the pieces will meet specifications. On the other hand, STO allows for looser process specifications. By better modelling reality, extreme dimensional values of the manufacturing tolerance interval are considered less frequent; therefore, even if specification limits remain the same, the manufacturing tolerance band (i.e. the process capability σ) could be relaxed just by accepting that a small part of the pieces may be rejected.

6

Provided that the simplification with respect to single and recursive errors holds.

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Garlasché M. Tolerances optimisation in the mechanical design of components

1 2

3

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Figure 4.10: Frequency plot of dimensional outputs: (1): WCO assumes no distribution, therefore all pieces could fall in a smaller band inside specification. (2): If a process follows normal distribution, WCO requires a process with σ such that 100% of pieces pass specifications. (3): STO allows for relaxed process capability but few pieces will be Out Of Specification. The STO approach saves money in production costs, while increasing the number of rejects. Therefore, the ideal condition to be found is the one that minimises the combination of these two costs. This latter can be defined as True Batch Cost (TBC) and is obtained by dividing the cost of a batch production by its acceptance fraction7. As stated above, cost-tolerance relations are often difficult to obtain, therefore the search for the minimum TBC in a continuous tolerance interval may be unfeasible. The same philosophy, though, can be more easily applied to a discrete set of tolerance values. Given the specification limits, a common way to proceed is therefore to vary the manufacturing tolerance band (therefore the capability) such that 2Zσ USL  LSL where Z is the real number between 0 and 7 defining the Confidence Interval (CI) of manufactured pieces that will fall inside specification limits (see Table 4.2) for each side of the curve (i.e lower and upper with respect to the mean value).

7

If statistical occurrence of nonconformities is designed at reasonable values, as a first approximation the percentage of rejects among reproduced pieces may be disregarded. Cost analysis on re-machining of rejects may be treated separately.

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Garlasché M. Tolerances optimisation in the mechanical design of components

As a reminder, the value of the confidence interval is obtained by integrating the Gaussian curve between the chosen extreme values, that is: USL

pCI

³f

Gauss

LSL

 ZV

³

fGauss

 ZV

Where pCI is the fraction falling within the confidence interval and fGauss is the probability density function of the Gaussian distribution. The second equality is due to the centred distribution hypothesis. This value represents therefore the net area of the region bounded by the Gaussian curve, the zero-frequency axis and the vertical lines representing specification limits. Table 4.2: List of Zσ values with relative percentages of Confidence Interval

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zσ 1σ 1.645σ 1.960σ 2σ 2.576σ 3σ 3.2906σ 4σ 5σ 6σ 7σ

% within CI 68.268 949 200% 90% 95% 95.449 973 600% 99% 99.730 020 400% 99.9% 99.993 666 000% 99.999 942 669 700% 99.999 999 802 700% 99.999 999 999 744%

% Outside CI 31.731 050 800% 10% 5% 4.550 026 400% 1% 0.269 979 600% 0.1% 0.006 334 000% 0.000 057 330 300% 0.000 000 197 300% 0.000 000 000 256%

ratio outside CI 1 / 3.1514871 1 / 10 1 / 20 1 / 21.977894 1 / 100 1 / 370.398 1 / 1000 1 / 15'788 1 / 1'744'278 1 / 506'800'000 1 / 390'600'000'000

Amongst the different values of Zσ, two have been taken into consideration for the half-cell profile tolerance analysis, i.e. the 3σ and the 6σ. The 6σ interval is connected to the homonymous methodology developed by the Motorola Corporation in the mid-1980s. This business management strategy seeks to improve the quality of process outputs by identifying and removing the causes of defects and minimizing the output variability both by acting on manufacturing and on the business processes. By keeping such high deviation requirements, it produces long-term defect levels below

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Garlasché M. Tolerances optimisation in the mechanical design of components

0.002 DPMO (Defects Per Million Opportunities), thus allowing for representative samples analysis. On the other hand, the more traditional quality model ‘3σ’ focuses mainly on the manufacturing processes and produces long-term defect levels around 2700 DPMO.

4.5. Old and new tolerance definition procedures

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The half-cell design is a joint work between the mechanical and the RF departments. Many parameters, in fact, need to be determined: in particular the profile tolerance values. In the first step of the design procedure, the RF department studies the right geometry of the cells in order to excite the TM010 mode and make them resonate at the nominal frequency. Once the ideal geometry of the cells is defined, the mechanical dept. determines the geometrical design of the single half cells and defines a starting value for their profile tolerance. Given this first set of tolerances the RF dept. performs a worst case analysis and obtains the frequency range around the theoretical value, inside which the cavity could resonate due to the possible geometry shifts. This frequency range has to be lower than the one adjustable with tuning, which is proportional to the inserted volume. As seen, the inserted volume is geometry dependent, therefore a few iterations are done in order to obtain tuneable cells compatible with the loosest profile tolerance values. In the old procedure, once this value for the RF acceptance band is set, it automatically defines the acceptance band specified for manufacturing: LSLRF

tolmanuf _ min

USLRF

tolmanuf _ MAX

This means that all the pieces accepted at manufacturing will also meet RF specifications (Figure 4.11). Nevertheless, an indirect dimensional control is also done during the tuning procedure, as a faulty half-cell would cause out-of-range, un-tuneable resonance. In the perspective of product optimisation, this design procedure has been revised in order to avoid any superfluous constraint. With this in mind, it has been determined that the equality definition between RF and manufacturing specifications could be avoided.

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Garlasché M. Tolerances optimisation in the mechanical design of components

Figure 4.11: The manufacturing tolerances are equal to RF LSL and USL specs, therefore there won’t be any out of specification (OOS). Therefore, for the new procedure an important step has been taken in redefining such values so that: %tolmanuf _ min

USLRF

%tolmanuf _ MAX

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LSLRF

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Garlasché M. Tolerances optimisation in the mechanical design of components

Figure 4.12: The manufacturing specs are looser than the RF requirements, therefore some pieces accepted after machining won’t be accepted for RF.

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By doing so, the manufacturing capability may be relaxed, thus allowing for profile tolerance values above the 30μm band specified in the old procedure due to RF acceptance limits. Still, such action could not be justified and the resulting rejects wouldn’t be quantifiable without some hypothesis on the manufacturing output behaviour. Therefore, the second step for the new procedure has been to assume a STO approach to production, with a centred normal distribution of the produced profiles.

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Garlasché M. Tolerances optimisation in the mechanical design of components

Figure 4.13: Comparison between RF specs and manufacturing approaches: the old WCO approach (could be seen as a 7σ STO), the 6σ, and the 3σ. Figure 4.13 depicts the two STO-related approaches analysed for the half cell production; whereas the old procedure can also be seen as a STO approach where the process capability is set so that 100% (i.e. 7σ) of production will fall inside RF specifications: 'tolmanuf 7V manuf USLRF  LSLRF Instead, for the two new approaches one has: 'tolmanuf ( 7V manuf ) ! USLRF  LSLRF

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'tolmanuf



7V manuf ! USLRF  LSLRF

6V manuf

3V manuf

This means that in the 3σ and 6σ case the capability will be relaxed so that, respectively, circa 99.99% and 99.73% of the pieces will meet the RF specification. Evaluating the two possible STO approaches for the half cells manufacturing, one has that the benefits of applying the 6σ one would be: a) The cost of rejects would still be practically zero (0.002 DPMO); even in the case of a 1.5σ drift of the average value during production, the DPMO value would be around 3.4. b) The possibility of representative sample analysis would save money by reducing the cost for quality controls.

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Garlasché M. Tolerances optimisation in the mechanical design of components

On the other hand: x Passing from a 7σ-like procedure to a 6σ one wouldn’t allow a radical tolerance relaxation. x Cost for quality control would only be reduced for manufacturing, as a 100% RF check cannot be avoided while tuning. x Due to how it has been conceived, 6σ is more functional when applied down to final products for customers (to reduce the number of non-conform products on big batches) rather than only to components to be assembled. This is especially true in the case of high cost-risk and small batch products, such as for a medical device like LIGHT. Therefore 6σ has been found not suitable for the definition of halfcell manufacturing. On the other side, even though with the more traditional 3σ a complete manufacturing quality control would still be needed: x given the small batch size of the half cell production (1280 pieces), the number of rejects would settle around only 3÷4 defects. x This approach would allow for great tolerance relaxation (around a 70μm band) of manufacturing. Therefore the STO approach with a confidence interval of 3σ for acceptance has been proposed.

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Still, two observations must be made: a) Given the small number of half cells produced for the First Unit, the hypothesis that manufacturing will follow a normal distribution has still not been verified. Nevertheless the company commissioned for production has proven extreme control over eventual errors. Furthermore a possible variation in the characteristic curve would only determine a change in the final price reduction but would not change the philosophy behind and the advantageous trend of tolerance relaxation. b) The control via profile specification (GD&T) is different from a typical dimensional tolerance control, as it requires a series of dimensional measurements all along the checked profile. In order to lighten the verification of the output distribution, some data filtering can be done by considering just the max. and min. values measured for each half cell, instead of the complete profile set.

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Garlasché M. Tolerances optimisation in the mechanical design of components

4.6. Numerical case evaluation Once the 3σ procedure has been chosen as best proposal for future productions, a few target quotations (especially near the 6σ and 3σ related values) have been obtained for the half cells batch machining. From such values it has been determined that the half-cell manufacturing roughly follows the cost-tolerance exponential law (Speckart). It has been also found that the new proposed approach will allow for a 16% cost reduction in the machining of the single unit. Hence, a rough comparison between the previous and new TBCs helped assessing a useful parameter for decision making. For the old manufacturing, given an approximate cost of 100 € per half cell (HC) and the 100% acceptance (WCO condition): ª € º TBCold 1280 > HC@ u100 « 128000 > € @ ¬ HC »¼ In the 3σ case, the 99.73 acceptance percentage would lead to 4 nonconformities (2 under the LSL and 2 over the USL) for the overall production. Given the price reduction, though: ª € º TBCnew 1280  4 > HC@ u 100  16 « 107856 > € @ ¬ HC »¼ Providing a general cost saving of more than 20000 €. Furthermore, among the nonconformities, the 2 with values over the USL could be re-machined. As a first estimation, the re-machining cost has been given as equal to 0.4 times the manufacturing cost: TBCnew Copyright © 2013. IOS Press, Incorporated. All rights reserved.

 remach.

(1280  2  2·0.4) [HC] u (100  16) [€ / HC]  2[HC] u CX[ € / HC] 107755  2CX > € @ Still, given the small batch, one can see that re-machining wouldn’t provide considerable gain; therefore no further inquiry on the logistics costs Cx has been pursued.

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Garlasché M. Tolerances optimisation in the mechanical design of components

It is also interesting to determine the robustness of such approach in relation to one of the hypotheses, i.e. the output distribution centring on the specifications mean value. The condition TBCnew TBCold is reached when the number of half cells to be produced with the new approach equals 1523 units. This means that, in order to complete the production (1280 units), the minimum percentage of conform half cells should be 84%. Given Δ as the shift between the mean value of production and the mean value specified, such that § USL  LSL · ' abs ¨  P profile ¸ 2 © ¹ one can determine ΔMAX by solving the integral USL

%CI

³f

Gauss

LSL

while keeping the same process capability, that is: 2 ˜ 3V USL  LSL

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From such calculations one finds that until Δ remains lower than the value 2σ, the new proposal will still be more advantageous than the old one.

Figure 4.14: Mean value drift of 2σ causes higher than expected nonconformities over the USL.

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Garlasché M. Tolerances optimisation in the mechanical design of components

4.7. Conclusion As expected, the production of the First Unit prototype has given better knowledge on the overall production procedure and therefore on the improvement of LIGHT’s industrialization level. In this chapter, one of such improvement steps has been analysed. The latter has brought to a considerable gain: just through interaction with the manufacturing counterpart and by changing tolerance specifications, 20000€ can be saved in any future production. The adopted method is obviously even more profitable in case of large batch production, especially if re-machining of the nonconformities may be implemented. For what concerns the choice of 3σ over 6σ, not always the best performance procedure allows for the optimal final product. Therefore it is advisable to focus more on what are the best parameters for choosing the quality method rather than opting for the most performing method itself. Finally, the analysis shows how at any level, even in the production of high-cost and complex machines such Linacs, it is always advisable to question procedures. As embedded as they may be, in fact, such dogmas may just be due to old debatable choices.

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Bibliography 1. Pahl G., Beitz W., Feldhusen J., Grote K.-H. (2007), Engineering Design: A Systematic Approach, Springer 2. Chase K.W. (1999). Tolerance Allocation Methods for Designers. Retrieved from http://adcats.et.byu.edu/home.php 3. Chase K.W. (1987). Design Issues in Mechanical Tolerance Analysis. Manufacturing Review, ASME, vol.1, no 1 4. PSI (2008), Proton therapy at PSI. Retrieved from www.psi.ch 5. Amaldi U., et al. (2010), Accelerators for hadrontherapy: From Lawrence cyclotrons to linacs, Nuclear Inst. and Methods in Physics Research A, 620(2-3), 563-577 6. Wilson R. (1946), Radiological Use of Fast Protons. Massachussets: Research Laboratory of Physics, Harvard University of Cambridge. 7. www.tera.it

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Garlasché M. Tolerances optimisation in the mechanical design of components

Topics for discussion and self-study 1. Make inventory of the main concepts and their coupling and interactions with the larger context outlined in this case study. As starting point you may use and revise/ correct/ elaborate the following visual transcript (also magnified into full-sized segments at the end of this section). Then transform the transcript into an idea network to eliminate redundancies and identify and formalise unique idea relationships.

push product’s industrialisation level

1st prototype

etc

tolerances optimisation for mechanical design of half-cells 3σ

(choice of) LIGHT design architecture cause physical and phenomena effect

uncertainty

systems decomposition wider manufacturing tolerances

tight operational tolerances

iterate until convergence

sensitivity to uncertainty?

ope requ rational irem ents ma ring nufactufeas ibility

state of art

constraints

cost/

remedy defects and variability

start from a nominal design

redesign analyse worstcase conditions scenario

enabling operation economical (hadron reasons therapy) technical context of reasons operation functionality (goal) risks

(otherwise-) underlying operation

analysis redesign to cons train reduce sensitivity ts to uncertainty evaluation

tuning

n

^

production of components

etc

sig

risk-cost analysis

modular

de

choices

prove concept

to: build prototype

Linac

etc

6σ (remove causes of defects and variability) not applicable in this context

optimise design

optimise industrialisation

coupled goals

costs feedback loop

costtolerance relationships

product goal (wishes)

impossibilities possibilities

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target moving organs

multipainting

2. What are the main relations and causalities that connect the items identified in question 1? How are they translated into processes and how effective are they? 3. Map the processes and challenges outlined in this case study onto two other case studies of your choice (also from this volume) and compare them. What conclusions do you draw? What advice can you give?

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Garlasché M. Tolerances optimisation in the mechanical design of components

1st prototype

^

etc

choices risk-cost analysis

production of components

etc

6σ (remove causes of defects and variability) not applicable in this context

optimise design

optimise industrialisation

coupled goals

e

tolerances optimisation for mechanical design of half-cells 3σ systems decomposition

wider manufacturing tolerances

tight operational tolerances

redesign to con reduce sensitivity to uncertainty evaluation

tuning remedy defects and variability

analysis

state of art

iterate until convergence

sensitivity to uncertainty?

start from a nominal design

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redesign analyse worstcase conditions scenario

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Garlasché M. Tolerances optimisation in the mechanical design of components

push product’s industrialisation level

optimise design

optimise industrialisation

coupled goals

prove concept

to: build prototype

modular Linac

oduction of omponents

etc LIGHT

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e worstnditions nario

n

ope requ rational irem ents cost / ma n ufa ring feas ctuibility

to cons train tivity ts nty evaluation

ma esign

enabling operation economical (hadron reasons therapy) technical context of reasons operation functionality (goal) risks

(otherwise-) underlying operation

analysis

sensitivity to uncertainty?

sig

cause physical and phenomena effect

uncertainty

de

optimisation for esign of half-cells

(choice of) design architecture

constraints

costs feedback loop

costtolerance relationships

product goal (wishes)

impossibilities possibilities target moving organs

multipainting

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Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved. doi:10.3233/978-1-61499-242-4-72

5. Design of the Océ ColorWave 600 carriage Draad A. (Aswin) Lead designer, R&D department, Océ-Canon, Netherlands, www.oce.com

Summary The ColorWave 600 printer was introduced in 2008 and this paper presents the design of the carriage, which transports the print heads accurately up and down the printer. Positioning of the print heads, especially self-positioning, and thermal aspects are discussed which have largely shaped the design of the carriage.

5.1. Introduction

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This paper starts with a short introduction of the ColorWave 600 printer itself and some general comments on the carriage design; we will dive deeper into the challenges associated with the selfpositioning of the print head in the carriage and some thermal behaviour aspects. Then, we will discuss the design phases and the special measurement tooling we developed to be able to measure the carriage behaviour in all six degrees of freedom when moving up and down the guidance, which is almost two meters long.

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Draad A. Design of the Océ ColorWave 600 carriage

Figure 5.1: ColorWave 600 print system (left), TonerPearl cartridges (top right) and print head (bottom right). Shown in Figure 5.1, the ColorWave 600 printer is a very high productive colour printer, being able to print two A0 sheets per minute, which is equal to two square meters per minute. It is based on CrystalPoint technology, which Océ developed. The basis for that are the toner pearls, which is a kind of gelling toner ink. Obviously if you want to make a very productive system the entire system needs to be productive and not just a very productive print head. So the ColorWave 600 has among another six roles, the possibility for prints to be collected on top to support a productive workflow.

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5.2. Principle of the inkjet The ColorWave 600 carriage contains 8 piezoelectric print heads (2 per colour cyan, magenta, yellow and black), one of which is presented in Figure 5.2. The TonerPearls (it is a gelling toner) are being melted in the melting unit and heated up until 130°C. The print head itself has a graphite base with ink channels. Actuation of the piezoelectric finger above an ink channel pushes the molten toner through the nozzle, which flies to the print surface and solidifies. The print head also has an electronics board with a large heat sink for cooling the ASIC which drives the print head. This configuration leads to a rather top-heavy print head, which has to be positioned accurately and withstand the accelerations during the turning of the carriage.

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Draad A. Design of the Océ ColorWave 600 carriage

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Figure 5.2: Print head for CrystalPoint technology Figure 5.3 shows a magenta print head printing droplets when moving from left to right and from right to left (in the next swath). Suppose we want to jet a line at position c. The droplet has a velocity in both the vertical direction as well as in the carriage movement direction. Thus the trajectory of the droplet is inclined and it arrives at a different horizontal position on the paper (positioned on the print surface) than where it has been jetted. The carriage moves further down the guidance and then it returns to come back in the other direction. Droplets jetted in the right-to-left swath that need to form a line at position c also need to be ejected earlier to arrive at the paper exactly on position c. So in order to obtain a sharp line/image, the jet timing needs to be tuned depending on droplet velocity, carriage speed and movement direction of the carriage. But this isn’t the ideal world; both the guidance as well as the print surface are not perfectly straight; there is easily a couple of hundred microns non-straightness of these parts which are more than a meter long. If the jet timing would not be corrected for this, the trajectories of the two droplets who were supposed to end up at the same position either cross each other (position d) or never even meet each other (position e). This is only one example of tolerances which might affect the positioning of the droplets on the paper, which in the end will destroy the print quality. And that is what it is all about; give the customer a very good print, crisp lines and nice colours. The human eye is very sensitive to droplet mispositioning, thus leading to narrow tolerances that have to be met.

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Draad A. Design of the Océ ColorWave 600 carriage

Figure 5.3: The principles of aligning inkjet droplets

5.3. Mechanical layout inkjet printer

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Figure 5.4 shows a ColorWave 600 printer with all the covers taken off. In the middle is the guidance over which a carriage moves up and down. Below that is the media handling with the roles in the drawer. It transports the paper underneath the print head. On the top left the ink supply is located which delivers the toner pearls in the melting units of the corresponding print heads. Below the guidance on the right hand side, the maintenance unit is located which cleans the print heads to keep the nozzles in shape. It consists of an array of eight wipers, each for one nozzle plate/ print head. Obviously there is more to a printer than just mechanics (e.g. controller, image processing, measurement & control), but within the context of the design of the carriage only the mechanical layout is treated.

Figure 5.4: Basic ColorWave 600 inkjet engine without covers

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Draad A. Design of the Océ ColorWave 600 carriage

Figure 5.5: ColorWave 600 carriage carries 8 print heads across the medium A more close-up view of the carriage is given in Figure 5.5. The eight print heads are placed closely together. The melting unit openings can be seen at the upper part of picture. Also the heat sinks for cooling the driver ASICs are clearly visible. The design of the carriage is very compact, which is beneficial for reduction of heat losses and accuracy.

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5.4. Design aspects of the carriage Some general aspects on the carriage design are shown in Figure 5.6. The printer has a resolution of six hundred dots per inch, i.e. 42 μm per pixel. The thickness of a human hair is about 70 μm, just to give a reference. In order to get good print quality, the droplets typically need to be positioned within half a pixel, thus within 20 μm. This needs to be done at least within the carriage over a distance of more than 100 mm’s. However, the 20 μm is not just one tolerance but it is a tolerance chain which is distributed over the print heads, the carriage, the guidance, and so on. There are a lot of parts being involved and you still need to get the print heads within these 20 microns. There are also thermal aspects to be considered because the print heads are very hot, which in general has an adverse effect on accuracy. Also the print heads need to have an even temperature, because a temperature gradient of more than 2°C inside the print head will lead to a different viscosity of the ink being jetted. That again will lead to a different velocity of the droplet resulting in mispositioning. Another aspect is that power consumption needs to 76

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Draad A. Design of the Océ ColorWave 600 carriage

be minimised, especially in low power mode, because the printer should not consume a lot of energy when it is not being used.

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Figure 5.6: Mind map for ColorWave 600 carriage Finally, tolerances of 20 microns are very easy to cope with, because in Veldhoven, where ASML is building semi-conductor manufacturing machines, they are not talking about microns but about nanometres. So what is so difficult about twenty microns then? That is the cost target, because if you would compare a wafer stepper (to make the comparison); it has tolerances in the range of 20 nm, but it would also cost about 20-40 million dollars or Euros, whereas a printer of Océ would cost typically 20 to 40 thousand Euros. So we have a factor of thousand larger tolerances but we also have a factor of thousand less money which we can spend on the printer. The cost target is what makes designing a ColorWave 600 carriage challenging. The mind map is an effort to write down all kinds of things which need to be taken in account in the design of such a carriage. We have eight very hot print heads, so thermal issues need consideration as well as positioning issues. It carries too far to discuss all the aspects but many aspects are probably recognised as being relevant. We focus on thermal aspects later and start elaborating on selfpositioning.

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Draad A. Design of the Océ ColorWave 600 carriage

5.5. Self-positioning The general design of the carriage is that we have a frame which is very stiff but it is not accurate. The 8 print heads are placed inside a matrix plate, coloured red in Figure 5.7. The matrix plate is accurately positioned relative to the guidance axes using leaf springs with adjustment mechanics build in using elastic joints. The leaf springs also function as a thermal barrier for the hot matrix plate with print heads to the colder carriage frame.

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Figure 5.7: The matrix plate mounted in the carriage frame using leaf springs (left) and the first design for print head positioning using hollow bushes (right) It is very important to remember that the positioning accuracy of 20 microns is about relative positioning accuracy for the print heads relative to each other. It is not about an absolute accuracy, which makes a big difference. Repeatability is very important, so if you take out a print head and put it back in again it needs to return to its original position within very tight bounds of several microns. Since we use piezoelectric print heads which last the life-time of the printer, we also need the positioning mechanism to be very reliable. It has to be able to cope with e.g. dust, toner spellings, etc. It should be preferably be possible for a customer to replace a print head, although we decided -since they are very expensive- to not let the customer do this, but it should be possible. When we started the design of the positioning concept we first came up with the design shown in Figure 5.7. We used accurate products; an accurate matrix plate and accurate print head components. In the print head we milled a hole

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and we placed hollow brass bushes inside. They centre the components in the middle of the hollow bush. This works fine in a R&D environment, with people having golden hands, but this would not have worked in a product in the market, because it is not robust enough. In order to get this functioning we need a bush of 0.3 mm thickness with very tight diameter tolerances, both on the bush, on the print head parts and in the matrix plate. This would make it very expensive and also because we have a very good thermal contact of the print head and the matrix plate we need a heated matrix plate. Otherwise the print head would get 'cold ears' and that would lead to the problems explained before. Furthermore, during printing the print heads might experience paper crashes. If the paper is not entirely flat on the print surface, the carriage might run into it and then the paper gets crumbled underneath the carriage and pushes the print head out of position. Since we have no means of detecting that or correcting for it, we need to make sure that, once the paper is removed, the print head returns to its original position: We need self-positioning and the design with bushes is not selfpositioning. So we decided we needed a different positioning concept; we replaced the hollow bushes with ceramic spheres, they are very accurate and relatively cheap to obtain. We made a conical hole on the one side and a V-groove at the opposite side of the matrix plate (see Figure 5.8). The conical hole fixes three degrees of freedom and the V-groove two, leaving the rotation of the print head to be fixed. We do that with a third sphere on top of the print head. On top of the print head parts shown in Figure 5.8 are the melting unit and the electronics, so this is not the entire print head shown here.

Figure 5.8: Positioning concept for print heads in a matrix plate using ceramic spheres To be able to guarantee self-positioning, the clamping construction is crucial which is all about friction. Self-positioning is very difficult to

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Draad A. Design of the Océ ColorWave 600 carriage

predict especially in a 3D geometry, so what we need is visualization of latitudes to be able to understand where it is critical and where not and how large the window of self-positioning is. We should have a good method of seeing how various designs score on self-positioning. It would be very nice to have a physical understanding of the behaviour of the print head while self-positioning. Self-positioning is crucial for this product, if we don’t have self-positioning and we don’t measure the position of the print head we have no means of knowing something is wrong. So we need to be able to guarantee that the print head is positioned accurately all the time.

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This has lead us to develop a simulation program ourselves to judge the self-positioning of various designs. The equations of motion for the print head are solved time-dependently. The print head is modelled as a solid body, having three interfaces with three spheres and we introduce Coulomb friction, both at the contact points but also at the points on which forces act, because if a spring is being pushed on a print head this also introduces a friction force. The procedure is that one of the spheres is moved out of position after which the motion of the print head in time is simulated to check whether or not the print head moves back into position. Two examples of such simulations are shown in Figure 5.9. In the left picture the sphere at the top of the print head is displaced. The spring force pushes the print head back towards the datum plane and when it touches, it bounces back and after a while the print head is returning to its good position (all distances to the contact surfaces are zero again).

Figure 5.9: Bouncing behaviour in self-positioning. Left: 3rd support point (preventing rotation); Right: Sphere hits cone, V-groove comes loose

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In the right picture the sphere in the cone is moved out of position. In the simulations we didn’t use a perfect cone but we simulated a cone using 16 surfaces/faces. That is why Figure 5.9 shows 16 grey lines for the conical hole, each representing one of the 16 faces of the cone. These distances to the surface are being reduced. The sphere touches the cone at approximately 0.003s and then the other side of the print head comes loose in the V groove. Those are the blue and the green line. So these time-dependent results also give a physical understanding of what happens during self-positioning. This helps in getting a better design. We defined 7 initial positions for which the self-positioning behaviour is simulated (one for each degree of freedom except for the cone where we used 4 instead of 3). Although there is no mathematical proof that this covers all possible situations, it probably gives a fairly good indication of the self-positioning latitude. Being able to visualise the simulation results is also very important. An example of a self-positioning simulation of a particular print head positioning design is shown in Figure 5.10. The black solid and dashed lines are just reference lines. The coloured lines represent the boundary of self-positioning for the 7 initial positions as a function of the clamping forces F1 and F2 (see Figure 5.8 for an explanation). The grey shaded area represents the self-positioning area for the entire print head, i.e. it is the joint area of combinations of clamping forces for which the print head returns to its original position for all 7 initial (displaced) positions.

Figure 5.10: Determination of latitudes for self-positioning

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Obviously we needed to check whether these calculations are correct so we performed self-positioning measurements by pushing the print head out of position and measuring whether it returns to its original position. The comparisons of the simulations with the measurements are shown in Figure 5.11. The left picture shows the simulation (shaded grey area) and the measurements. In red there is no selfpositioning, in yellow it is almost self-positioning and in green it is self-positioning. The simulations and the measurements are in fair correspondence giving confidence that we are actually able to predict self-positioning. The right picture shows measurements of a different design in which the transversal stiffness of the clamping mechanism is further reduced. This significantly improves the self-positioning latitude. During the design process, the simulations showed that friction needed to be minimised, which is done using material choices; ceramic spheres and steel have a very low friction. But the key solution was to replace friction with something else, replace friction with a low stiffness in a clamping direction which is nonefunctional. This significantly increases the self-positioning latitude.

Figure 5.11: Measurements for stiffness in two lateral directions The simulations have guided the design towards a bead-string based positioning mechanism, as shown in Figure 5.12. It shows a bare carriage without print heads and everything else. The coiled springs provide the clamping force F1 and the bead-string limits the rotation of the print head around the 2 bottom spheres. The bead-string is very stiff in the left-right direction (i.e. the direction in which the carriage moves) but much less in the normal non-functional directions. In other words, the transversal stiffness of the clamping mechanism is

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low. In this way, if the print head is being pushed out of position it doesn’t need to slip and slide over the sphere, but it just feels the stiffness of the string, which is a much lower force than the friction force.

Figure 5.12: Bead-string concept for print head positioning mechanism

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5.6. Thermal design High accuracy normally is very difficult to achieve with high temperatures; temperature gradients are the enemy of accuracy. However, the thermal design of the ColorWave 600 carriage is not only about thermal expansion, but also other thermal aspects are relevant such as power consumption due to energy losses. The ASICs driving the piezoelectric print head are located above the print head, i.e. above 130°C hot parts. This is not beneficial for cooling down ASICs. In order to have functional heat sinks we need to insulate the hot print heads from the rest of the environment and the ASICs cooling heat sinks. This is why the print head electronics with the ASICs and heat sinks are kept outside the insulation box. All these aspects have interactions and determine the thermal dynamic behaviour of the carriage and thus the positioning accuracy. Temperature gradients in the matrix plate should be minimised since they would lead to deformations. The carriage is also subject to dynamic thermal behaviour, because there is a difference in insulation when printing and when in standby. Because we want to

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reduce power consumption when not printing, the carriage is placed in a thermal box including an insulated bottom cover. Obviously this prevents jetting to the paper, so when it starts printing the thermal boxes opens and the carriage starts moving at approximately 1 m/s. This wind will cool down the matrix plate. In the first prototype carriage design there is a good thermal contact between the print head and the matrix plate (see Figure 5.7), the graphite of the print head is in direct contact with the matrix plate. But in the new design with the spheres, the print head is insulated from the matrix plate by the ceramic spheres. The contact area is very small and the ceramic material has a very low thermal conductivity. Thus heating the matrix plate is no longer needed, which reduces the costs of the heating elements and also increases reliability because the heating elements cannot break when they are not there. However, a non-heated matrix plate shows much more dynamic temperature variations between printing and not-printing than a heated matrix plate.

Figure 5.13: Thermal behaviour of a non-heated matrix plate when printing is started Measurements show that on various positions of the matrix plate temperature changes of 30°C are present, as illustrated in Figure 5.13. Thus thermal expansion will result in a lot of microns. The shape of

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Draad A. Design of the Océ ColorWave 600 carriage

the matrix plate has been measured and modelled when it is subjected to these temperature gradients but also the deformation due to temperature gradients. The shape of the matrix plate is shown in the matrix plate deforms in a barrel-shape. This is easily explained by the temperature of the ribs. Ribs in between 2 print heads will be close to the 130°C. But on the outside there is only one print head and in addition there is some thermal leakage through the mounting point. The conical holes which determine the position of the print heads in the X-direction will therefore vary for each print head. However, it is not the absolute position which is relevant but it is the relative position which determines the alignment of the print heads. The difference in X-position is relatively small, it is only a few microns, and it is considered acceptable.

Figure 5.14: Deformation of the matrix plate due to thermal gradients

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5.7. Design phase Within Océ we use several design phases. LabModel 1 is used to show the first proof of principle, the architecture of the design is verified and the feasibility of the product concept is shown. Once this is done, LabModel 2 can be designed in which decompositions are verified: e.g. dot-positioning, cost price, reliability, etc. So basically after this phase most of the risks have been eradicated. Then engineering can start including design for X, unit specs and so on. And then the last phase within R&D is called review engineering prototype. That basically is building a printer based on the entire documentation package produced by R&D. The goal is to check if

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this documentation guarantees a good operation of the printer. If so, the project can be transferred to manufacturing.

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Figure 5.15: A physical model of the LM2 carriage (top) and the production carriage (bottom) Figure 5.15 shows the LM2 carriage having relatively large electro parts, 8 print heads and many thermocouples, which is fine in R&D but not a nice interface to electronics in a final product. The carriage frame is milled from a solid aluminium block, thus simulating a cast aluminium carriage frame. However, since the carriage frame only needs to provide stiffness and not accuracy (which is delivered through factory adjustments), we decided to make the carriage frame out of sheet metal, which is cheaper and more flexible in the design. Also the print head orientation has been rotated because we wanted to reduce the length of the flexes for cost reduction but also for electromagnetic interference reasons. The red dots mark the screws which we use for the adjustment of the accuracy of the matrix plate in

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Draad A. Design of the Océ ColorWave 600 carriage .

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the printer. The red handle is to open up the carriage and to be able to replace the print heads. It is very easy to do and it even can be done by customers, if needed. During the development of the ColorWave 600 we had quite some discussions on which unit caused the artefacts we saw on some of the prints. When we see a problem on the paper, how do we determine whether the print heads, the carriage or the media handling is causing the problem or something else? So we decided we needed to be able to just measure the mechanics itself which took quite an investment in both time and money. The measurement equipment is shown in Figure 5.16. It consists of a very solid granite measuring base on which the guidance with the carriage is mounted. Dummy print heads having retro cubes are placed in the matrix plate. Laser beams in combination with position sensitive devices (PSD's) are used to measure the position of the carriage while it is moving over the guidance (approximately one and a half meters). The PSD's can be used to measure 5 degrees of freedom and a laser interferometer is used to measure the position of the carriage along the guidance. In this way we can measure all six degrees of freedom of the carriage.

Figure 5.16: Equipment to measure the trajectory of the carriage/print heads over the entire width of the printer in 6 degrees of freedom An example of a measurement result is shown in Figure 5.17. Each line represents a swath of the carriage along the guidance. The

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eccentricity of the roller bearings is visible, resulting in some 2μm high frequency sinusoidal movement. Also a little bit of hysteresis with the carriage moving back and forth is found (not all lines falling on top of each other). One of the problems with this measurement tooling is that it is very sensitive to thermal effects. To minimise the influence of local temperature differences, leading to deflection of the laser beam, a large box is place over the entire setup. It is impossible to measure with print heads at 130°C, but even at room temperature we found that after some 10 seconds, the carriage movement mixes the air and the measurement is no longer accurately enough.

Figure 5.17: Equipment to measure the trajectory of the carriage/print heads over the entire width of the printer in 6 degrees of freedom

5.8. Conclusion The ColorWave 600 carriage is a rather complex thermo-mechanical design where we had to cope with very hot print heads and a strict cost target which makes it challenging. Self-positioning was vitally important for the product which is why we heavily invested in being able to accurately predict whether the print head positioning mechanism is self-positioning or not. The simulations have taken many weeks because of the entire window of operation that needed to

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be checked and the numerous design cycles. The solution was to replace friction with a low transversal stiffness, which was discovered by playing around with the model. It is also very important to be able to measure dynamically the behaviour of the mechanical parts; otherwise you always have discussions which unit causes the problems found in the prints.

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Draad A. Design of the Océ ColorWave 600 carriage

Topics for discussion and self-study

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1. Make inventory of the main concepts and their coupling and interactions with the larger context outlined in this case study. As starting point you may use and revise/ correct/ elaborate the following visual transcript (also magnified into full-sized segments at the end of this section). Then transform the transcript into an idea network to eliminate redundancies and identify and formalise unique idea relationships.

2. What are the main relations and causalities that connect the items identified in question 1? How are they translated into processes and how effective are they? 3. Map the processes and challenges outlined in this case study onto two other case studies of your choice (also from this volume) and compare them. What conclusions do you draw? What advice can you give?

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Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved. doi:10.3233/978-1-61499-242-4-93

6. Mechanical optimisation of a RF coupling system for a medical Linac by means of FMEA Mellace C. (Claudio) Project Engineer, ADAM SA, Geneva, adam-geneva.com

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Summary In this section, a case study on system optimisation applying Failure Modes and Effects Analysis (FMEA) and Failure Modes, Effects and Criticality Analysis (FMECA) methods is reported: the radiofrequency (RF) coupling system of a linear accelerator for proton therapy treatments is the topic of the analysis. In subsection 6.1, a general overview on hadron therapy, mainly proton therapy, is given; the advantages in using this medical treatment are highlighted, focusing on the growing need for cancer care, and pointing out solutions to bring proton therapy to patients using innovative systems as a response to the increased demand for cancer treatment. In subsection 6.2, basic concepts on Failure Modes and Effects Analysis (FMEA) and Criticality Analysis are described, with emphasis on the Tasks Identification and the Risks Evaluation Methods. In subsections 6.3 and 6.4, all the FMECA phases required for the optimisation of the RF coupling system, from the previous version dated 2001 to the up-to-date version of 2010, are investigated. Final conclusions are collected in subsection 6.5.

6.1. Hadron therapy Hadron therapy is a state-of-the-art medical treatment aimed at curing and controlling tumoural pathologies through radiation given by a beam of hadrons. What are hadrons?

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Hadrons are ions (subatomic particles) that can be precisely focused towards tumoural tissues after being boosted by complex medicalphysics accelerators. The indirect ionizations, caused by the interaction between ions and traversed matter, damage the DNA chain of the cancerous cells, prevent cell replication, reduce their dimensions and remove, as it is detected in the most part of the observed clinical cases, the carcinoma itself.

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Proton therapy and advantage for patients Proton therapy falls within the medical discipline of hadron therapy and it employs protons with energies ranging from 60 to 250 MeV, which allow the treatment of deep-seated tumours at up to a 30 cm depth. The main advantage of proton therapy is the ability to more precisely localise the radiation dose compared to other types of external beam radiotherapy. Since protons are heavy particles, they penetrate with minimal diffusion and slow down relatively fast when entering biological tissue. Most of their energy is deposited, with little scatter, at the end of their path in the so called Bragg peak region; Since protons are charged particles, they are easily formed as a proton beam ”pencil” that can be precisely guided towards the tumour. As a result, the dose is given to the tumour in a ‘conformal’ way and the effect on healthy tissues is minimised. Tissue selectivity is important when the tumour mass is seated in proximity of vital organs that must not be irradiated by the beam. For example, ocular neoplasia, head-and-neck cancers and spinal cord tumours are eligible for proton therapy. In case of neoplasia of prostate, lungs and gastroenteric apparatus this medical treatment is well-established and gives significant advantages to patients. Cancer incidence worldwide According to the GLOBOCAN 2008 Project (IARC, 2010) (Cancer Research UK, 2010), promoted by the International Agency for Research on Cancer (IARC), an estimated 12.7 million new cancer cases and 7.6 million cancer deaths occurred in 2008 worldwide (with 2.2 million new cancer cases in Europe). Furthermore, the GLOBOCAN 2008 Project estimates that by 2030 there will be about 21.4 million new cases diagnosed annually and that there will be over 13.2 million deaths from cancer. According to the detailed report supervised by Prof. R. Orecchia and distributed by the Italian Association on Radiotherapy (AIRO, 2003),

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an estimated 2% of cancer patients is eligible for proton beam therapy and for a further estimated 12% its potential therapeutic benefit is such that the use of proton therapy, instead of conventional therapy, is fully justified.

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Proton therapy facilities in operation To this day, few proton therapy medical centres are in operation worldwide. They are either cyclotron- or synchrotron-based facilities where protons are boosted up to 70 MeV and 150 MeV for ocular treatments and for head-and-neck tumours or paediatric treatments respectively. Beam energies higher than 150 MeV are useful for deep-seated tumours. All proton therapy facilities in operation are listed Table 6.1 (PTCOG, 2011).

Figure 6.1: Cancer Incidence Worldwide (2008)

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Country

Max. Clinical Energy

Beam Layout Delivery

LLUMC

Loma Linda, CA., USA 250

3G; 1H

PSI

Villigen, CH

72

1H

CPO

Orsay, F

200

2H

NPTC

Boston, MA, USA

235

2G; 1H

ITEP

Moscow, RUS

250

1H

CAL

Nice, F

65

1H

HIBMC

Hyogo, Japan

230

2G; 1H

CCO FPTI MD ACC

Clatterbridge, UK 62 Jacksonville, FL, USA 230 Houston, TX, USA 250

1H 3G; 1H 3G; 1H

PMRC, 2

Tsukuba, Japan

270

2G

HZB (HMI)

Berlin, D

72

1H

PNPI

St. Petersburg, RUS

1000

1H

UCSF-CNL

CA, USA

60

1H

WPTC

Zibo, China

230

TSL Svedberg Uppsala, S MPRI, 2 Shizuoka CC NCC JINR, 2

Synchrotron Cyclotron Synchrocyclotron Cyclotron Synchrotron Cyclotron Synchrotron Cyclotron Cyclotron Cyclotron Synchrotron Cyclotron Synchrocyclotron

Date

No. of Treated Patients

PT Centers

Table 6.1: Proton therapy facilities in operation Date of TOT

1990

14000 Oct-09

1984

5300 Dec-09

1991

4811 Dec-09

2001

4270 Oct-09

1969

4162 Jul-09

1991

3935 Dec-09

2001

2382 Nov-09

1989 2006 2006

1923 Dec-09 1847 Dec-09 1700 Dec-09

2001

1586 Dec-09

1998

1437 Dec-09

1975

1353 Dec-09

Cyclotron

1994

1200 Dec-09

2G; 1H

Cyclotron

2004

977 Dec-09

200

1H

Cyclotron

1989

929 Dec-08

Bloomington, IN, USA Shizuoka, Japan Kashiwa, Japan Dubna, RUS

200 230 235 200

2G; 1H 1G; 1H 2G; 1H 1H

2004 2003 1998 1999

890 Dec-09 852 Dec-09 680 Dec-09 595 Dec-09

PSI

Villigen, CH

250

1G

1996

542 Dec-09

NCC iThemba LABS

Ilsan, Korea Cape Town, South Africa

230

2G; 1H

Cyclotron Cyclotron Cyclotron Cyclotron SC cyclotron Cyclotron

2007

519 Dec-09

200

1H

Cyclotron

1993

511 Dec-09

INFN-LNS

Catania, IT

60

1H

2002

174 Mar-09

TRIUMF

Vancouver, Canada

72

1H

1995

145 Dec-09

RPTC

Münich, D

250

4G; 1H

2009

78 Dec-09

WERC

Wakasa, Japan

200

1H; 1V

2002

56 Dec-08

ProcurePTC

Oklahoma C. OK, USA 230

1G; 1H

2009

21 Dec-09

SC Cyclotron Cyclotron SC cyclotron Synchrotron Cyclotron

TOT

56875

It’s clear that more oncologic therapy facilities are required in order to deal with the constant increase of cancer incidence. The costs of a cyclotron- or synchrotron-based facility are very high: indeed, the first centres have been built inside, or close to, research

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centres where particle accelerators were already used for physics and biomedical purposes. Nowadays new proton therapy centres are on the way: even if they are built in proximity of hospitals and medical facilities (the so called ‘patient-oriented’ centres), their costs still remain high.

6.2. ADAM’s technological innovations For all the mentioned reasons, ADAM SA (Poppi, 2011) started in 2008 a R&D activity with the aim of producing a compact linear accelerator at high frequency which could reduce costs for proton therapy and could offer an accessible product for cancer treatment.

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The Linac for Image Guided Hadron Therapy (LIGHT), gathers all physics and medical requirements in order to guarantee the correct treatment of tumours by means of a protons beam. Furthermore, it brings great innovations in concept, design and manufacturing to be beneficial for production costs. The main features of LIGHT are: x Precision: the system has an active longitudinal modulation along the beam propagation axis with which it is possible to vary the beam energy, thus the depth, during the patient irradiation. On the contrary, with the passive modulation featured by cyclotrons (the fixed beam energy is degraded through the interposition of variable thickness absorbers in front of the patient, thus causing a beam quality degradation). Moreover, LIGHT has a dynamic transversal modulation that allows for a precise 3D treatment of the tumours (spot scanning); x Compactness: If compared to the cyclotron- or synchrotronbased facilities, LIGHT has more compact dimensions thus allowing for lower size and cost of the building.

Figure 6.2: 230 MeV Cyclotron + ESS

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Figure 6.3: 230 MeV Synchrotron + Injector

Figure 6.4: Linear Accelerator (LIGHT + Injector)

Figure 6.5: Cyclinac (LIGHT + 30 MeV Cyclotron)

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x

x

x

Modularity: LIGHT is conceived as an assembly of modular units. This results in offering complete freedom of customizing to radiation therapy centres, steering medical choices on a wide range of treatment energies. Moreover, LIGHT can be also addressed to all the small hospitals that can choose a 70 MeV accelerator, without precluding the possibility of extending its energy range afterwards by installing additional units, without the need of dismantling or re-installing a new system; Easy maintenance: modularity and compactness, together with simple design, allow for easy and fast maintenance which requires only short shut-down periods and it accomplishes the requirements concerning the minimum overall availability of the machine (95%); User friendliness: Linacs for proton therapy share very similar characteristics with the conventional x-rays Linacs. This peculiarity offers to doctors an easy approach to LIGHT by means of easy training courses.

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6.3. Failure Modes and Effects Analysis (FMEA) and Failure Modes, Effects and Criticality Analysis (FMECA) An overview of basic concepts Failure Mode and Effects Analysis (FMEA) and Failure Modes, Effects and Criticality Analysis (FMECA) are engineering methodologies used in product design and management, in order to improve system performances, resulting in higher reliability, better quality, increased safety, enhanced customer satisfaction and reduced costs (SAE 1993, 2001, 2009) (MIL-STD-1629A, 1980). FMEA is based on i) the identification of potential failure modes for an item (product, process, system, service, software), ii) the assessment of the risk associated with those failure modes (severity assignment), iii) the choice of the corrective actions. In addition, FMEA and FMECA are usually asked to comply with safety and quality requirements, such as ISO 9001, QS 9000, ISO/TS 16949, Six Sigma, FDA Good Manufacturing Practices (GMPs), Process Safety Management Act (PSM), etc. In general, FMEA is carried out through the following basic steps: Item(s) Task(s) analysis

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Failure(s) analysis mode(s) effect(s) cause(s) control(s) Risk(s) analysis Corrective action(s)

Risks analysis

What is the topic the analysis is focused on? What are the functions to be accomplished by each item? What could go wrong? What would be the consequences of each failure? Why would the failure happen? How could the failure be monitored? How could this failure impact on reliability? How would the results feed back into the design process to prevent same failures in future? What is the new risk level after the corrective actions?

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Mellace C. Mechanical optimisation of a RF coupling system

FMECA ANALYSIS

Figure 6.6: FMECA Scheme Item(s) identification In general, a fully understanding of the item(s) involved in the analysis is usually performed as first step, through a complete breakdown of the system.

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Task(s) Analysis This is a fundamental methodology in the assessment of functions which have to be accomplished by the item(s). A wide variety of different task analysis techniques exists, and it would be impracticable to describe all these methods here. In this framework, the intention is to describe the most representative methodology applicable to different types of task. Failure(s) Analysis Once items and tasks have been identified, the analysis proceeds with the Failures Analysis. Usually, it consists of a simple list which evaluates all possible (potential or actual) ways in which a component might fail (Failure Modes), by highlighting the consequences of those failures (Failure Effects), by identifying the causes of each Failure Mode (Failure Causes), and by determining the control processes required to detect the failures (Failure Control). Risk(s) Evaluation Methods It is fundamental to associate the risk with the potential failures previously identified through the failure analysis. Risks analysis 100

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Mellace C. Mechanical optimisation of a RF coupling system

helps to prioritise corrective actions and to qualify the improvements on the product/process. One of the most employed methods is the Risk Priority Number (RPN). It is based on the following four steps: 1. Rating the Severity (S) of each failure effect 2. Rating the Occurrence (O) for each failure cause 3. Rating the Detection (D) for each failure cause, including the evaluation of capability for the detection (‘are we able to detect it?’) and time detection (‘how much in advance can it be detected?’) 4. Calculating the RPN by multiplying the three abovementioned ratings: RPN = Severity × Occurrence × Detection

6.4. Case analysis: Mechanical optimisation of a RF coupling system for a medical Linac through FMEA

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Hereafter the concepts described in subsection 3 are applied to the mechanical optimisation of the Radio Frequency Coupling System of a medical linear accelerator. In this case, the purpose of FMEA/FMECA analysis is twofold. The first one is to investigate the quality of the system designed in 2001, namely its performances, reliability and costs. The second aim is to assess the improvements that can be applied to that system and the quantitative results in order to compare different solutions/versions. ‘Version 2001’: Item(s) identification on RF Coupling System As mentioned in subsection 3, the first phase is defined as Item(s) Identification. The hierarchy of hardware levels is enforced from the component, to the sub-systems, to the system and so on. A general layout of a proton therapy unit is reported in Figure 6.7. It usually consists of 8 systems, namely the accelerating system (1), the control system (2), the cooling system (3), the focusing system (4), the RF network system (5), the RF power system (6), the supporting system (7) and the vacuum system (8).The accelerating system designed in 2001 is composed of four tanks and by two RF Coupling Systems (Figure 6.7).

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Mellace C. Mechanical optimisation of a RF coupling system

Figure 6.7: A general layout of a proton therapy unit

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A general layout of a proton therapy unit: 1) Accelerating 2) Controls 3) Cooling 4) Focusing 5) RF Network 6) RF Power 7) Supporting and 8) Vacuum Systems.

Figure 6.8: The two accelerating structures (a) and the RF Coupling system (b) Each component of the RF coupling system assembly is identified both using a simple parts list (Figure 6.9) and a tree diagram, reporting the consecutive assembling phases (Figure 6.10).

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Mellace C. Mechanical optimisation of a RF coupling system

Item 1 2 3 4 5 6 7 8

Qty 2 1 1

ID Code LSM30WG003 LSM30WG001 LSM30BC001

1 1

LSM30PU001 LSM30BC002

2 2 1

LSM30BC009 LSM30BC013 LSM30BC011

1

LSM30BC007

1

LSM30BC004

1 1 1

LSM30BC008 LSM30BC013 LSM30BC003

9 10 11 12 13

Description LIL Flange Wave Guide Bridge Coupler body Pick Up Tuning Disk 01 PMQ Holder Lateral Tuner Assembly PMQ holder Assembly Vacuum Flange Bottom flange PMQ Central Tuner Tuning Disk 02

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Figure 6.9: Exploded view of the RF coupling system

Figure 6.10: Tree diagram of the RF coupling system components ‘Version 2001’: Task(s) Analysis of the RF Coupling System The RF Coupling system (2001) has to accomplish several tasks. As an example, a simplified list of tasks is reported in the following:

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Mellace C. Mechanical optimisation of a RF coupling system

x

x

x x

x

x

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x

RF Coupling: a correct design of the Bridge Coupler body (LSM30BC001) and of the Tuning Disks (LSM30BC002/3) is required in order to connect two consecutive tanks together in a single resonating module; RF Power Supply: the correct amount of power should be supplied to each accelerating structure from the Wave Guide (LSM30WG001), through a magnetic coupling iris. The reflected power should be minimised; RF Tuning: the Radio Frequency (RF) field must be correctly tuned, in order to compensate for potential mismatches due to mechanical tolerances and brazing. Vacuum Pumping: the whole structure shall perform under tight vacuum conditions. About 10-8 Torr is required in order to minimise the losses of protons colliding against other molecules. PMQ Alignment & Beam Focusing: since protons are charged particles, the beam tends to spread. So Permanent Magnet Quadrupoles (PMQs) are required to focus the beam along the Linac axis; Monitoring: a direct measure of the electro-magnetic field is required to validate the correctness of the performances; Stability: the BC Body LSM30BC001 has to guarantee stability to the whole structure during the assembling operation. For this reason, a brazing phase has been performed (Figure 6.11).

Figure 6.11: BC Body LSM30BC001 Finally, combining the item(s) identification and the task(s) analysis, a simplified tree diagram can be sketched (Figure 6.12). In principle, each component can affect the reliability of more than one task simultaneously (e.g. the Bridge Coupler Body 104

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LSM30BC001 has to accomplish three different tasks: RF Coupling, the RF Power Supply and Stability). For our purpose, these multi-task cases are neglected and the quality of each component concerns the consistency of just one task. However the reliability of each subsystem, resulting as an assembly of several components, can affect the functionality of some task domains, thus to which those components might belong to (For example, a failure regarding the sub-system LSM30CSSUB1, obtained by brazing the two subsystems LSM30BCSUB and LSM30WGSUB belonging to RF Coupling Domain and RF Power Supply respectively, might cause a failure on both tasks).

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‘Version 2001’: Failure(s) Analysis of the RF Coupling System An example of Failure(s) Analysis of the RF Coupling system is reported in Table 6.3.

Figure 6.12. Tree diagram of the RF coupling system components

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Table 6.3: Example of Failure(s) Analysis Task

Potential Failure Mode

Beam Beam not Focusing correctly focused

Potential Effect(s) of Failure Beam spreads on cavities wall

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Beams not correctly delivered to the target

S

Potential Causes of Failure PMQ not correctly installed (Assembly) Low gradient in PMQ (manufacture)

Current O Process Detection

D RPN

Mechanical tolerances analysis Beam analysis

PMQ holder not correctly machined (manufacture)

‘Version 2001’: Risk(s) Analysis of the RF Coupling System The Risk(s) Analysis plays the major role in evaluating the quality of the system: as explained, the rating of the Severity, the Occurrence and the Detection is a subjective task in order to evaluate the RPN parameter. Before proceeding with the analysis, the following assumptions must be made: x Each component/subassembly completely fulfils a Task, if it is Compliant with Mechanical Specifications. x All Potential Failure Modes result from NOT being Compliant with Mechanical Specifications. x The Severity has been rated proportionally to the costs (both manufacturing and assembling). x The Occurrence is equal to the percentage Outside Confidence Interval (OCI). Such OCI is determined assuming that the manufacturing/assembling processes will follow a Gaussian distribution. In particular, each process is rated from 1.645σ (10% OCI) for very delicate and complicated processes, to 2σ (4.55% OCI) for standard quality processes, to 3σ (0.27% OCI) for fully managed processes (Table 6.4). x The Detection is assumed to be a constant value and equal to 1, since the Current Process Detection is assumed to be a standard quality control of mechanical tolerances/dimensions.

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Table 6.4: zσ processes and corresponding OCI zσ 1σ 1.645σ 1.960σ 2σ 2.576σ 3σ 3.2906σ 4σ 5σ 6σ 7σ

% within CI 68.268 949 200% 90% 95% 95.449 973 600% 99% 99.730 020 400% 99.9% 99.993 666 000% 99.999 942 669 700% 99.999 999 802 700% 99.999 999 999 744%

% Outside CI 31.731 050 800% 10% 5% 4.550 026 400% 1% 0.269 979 600% 0.1% 0.006 334 000% 0.000 057 330 300% 0.000 000 197 300% 0.000 000 000 256%

ratio outside CI 1 / 3.1514871 1 / 10 1 / 20 1 / 21.977894 1 / 100 1 / 370.398 1 / 1000 1 / 15'788 1 / 1'744'278 1 / 506'800'000 1 / 390'600'000'000

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In the following, the Risks Analysis is performed for the sub-system LSM30CSSUB2, which involved mainly the RF Coupling and the RF Power Supply tasks (see Figure 6.12). Costs and reliabilities are evaluated for each of the processes (manufacturing and assembling). The Total Cost ‫்ܥ‬ை் and the Risk Cost ‫ܥ‬ோ௜ௌ௄ for this sub-system can be easily assessed, the resulting ‫்ܥ‬ை் is around 186.6 and ‫ܥ‬ோ௜ௌ௄ is around 44.67 (24% of ‫்ܥ‬ை் , see Table 6.5).

Figure 6.13: Risks Analysis Tree Diagram for LSM30CSSUB2

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Mellace C. Mechanical optimisation of a RF coupling system

Table 6.5: Total Cost and Risk Cost for LSM30CSSUB2 ID Code

Description

S

O

RPN

1

LSM30CSSUB2 Brazing

161.6+15+10=186.6

4.5%

8.40

1.1

LSM30BC004

15

0.27%

0.04

1.2

LSM30CSSUB1 Brazing

222.6+29+10=161.6

4.5%

7.27

1.2.1

LSM30BCSUB

212.6+10=122.6

4.5%

5.52

1.2.1(b)

Provisional Assembly BC Body LSM30BC001 manufacturing Tuning Disk 01 LSM30BC002 manufacturing Tuning Disk 02 LSM30BC003 manufacturing LSM30WGSUB Brazing Wave Guide LSM30WG001 Manufacturing LIL Flange LSM30WG003 Manufacturing LIL Flange LSM30WG003 Manufacturing

100+6.3+6.3=112.6

10%

11.26

100

10%

10

6.3

4.5%

0.28

6.3

4.5%

0.28

7+6+6+10=29

4.5%

1.3

7

0.27%

0.02

6

0.27%

0.02

6

0.27%

0.02

1.2.1.1 1.2.1.2 1.2.1.3 1.2.2 1.2.2.1 1.2.2.2 1.2.2.3

Brazing

Brazing

44.67

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Similar analyses can be performed for the evaluation of ‫்ܥ‬ை் and ‫ܥ‬ோ௜ௌ௄ for the LSM30BC007 and LSM30BC011 sub-systems (Vacuum Pumping and Beam Focusing tasks respectively).

Figure 6.14: Risks Analysis Tree Diagram for LSM30BC007 (a) and LSM30BC011 (b)

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Mellace C. Mechanical optimisation of a RF coupling system

Finally, the‫்ܥ‬ை் and the ‫ܥ‬ோ௜ௌ௄ for the whole RF Coupling System is assessed, recombining the previous results ‫்ܥ‬ை் is 223.1 and ‫ܥ‬ோ௜ௌ௄ is 30.7% of ‫்ܥ‬ை் .

Figure 6.15: Risks Analysis Tree Diagram for RF Coupling System LSM30CS01 Technical and Economical Evaluation The Assembly LSM30CS01 presents a high ‫ܥ‬ோ௜ௌ௄ (~30.7% ‫்ܥ‬ை் ), mainly due to the high cost of the Bridge Coupler Body LSM30BC001 and to the number of delicate and consecutive assembling operations required during the brazing procedure.

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6.5. Upgrades and improvements: Towards the RF coupling system ‘Version 2010’ Optimisation and design The optimisation stage usually follows the same phases of the flow chart generally used for the design phase (Figure 6.16). In the Clarification of Tasks phase, it’s essential to identify as fully as possible the functions that each item should accomplish, by distinguishing between needs and wishes. By analysing the previous version assembly, the idea of having a single system which could accomplish all the tasks was a wish, not a need. In this case it is possible to engineer the system with a new Specification, by reconsidering the tasks and subdividing them in three independent assemblies (Conceptual Design phase).

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Mellace C. Mechanical optimisation of a RF coupling system

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By having defined a new Concept, several preliminary layouts (possible solutions) have been checked for errors and cost effectiveness, by evaluating them with respect to technical and economic criteria. The results is the Definitive Layout (which concludes the so called Embodiment Design phase), ready for the complete detailed drawings and production documents (Details Design phase).

Figure 6.16: Flow chart for optimisation phases (Pahl et al., 2007) In next paragraphs, FMEA/FMECA analyses of the layout chosen as the Solution of the optimisation process are investigated. ‘Version 2010’: Item(s) Identification Three independent sub-systems were designed in order to comply with the tasks identified in section 6.2: 1. The LGHT-CPLS-01, mainly involved in the RF Coupling, RF Power Supply and RF Tuning tasks; 2. The LGHT-FOCS-01, involved in the focusing tasks; 110

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Mellace C. Mechanical optimisation of a RF coupling system

3. The LGHT-VPMP-01, involved in the vacuum pumping task. The division of tasks could be useful, in most cases, in order to reduce the risk costs. The exploded views and parts lists of the assemblies are reported in Figures 6.17, 6.18 and 6.19.

Item 1 2

Qty 2 1 1

3

2

4

2

5

ID Code LGHT-LILF-01 LGHT-LNWG01 LGHT-BCPC-01

Description LIL Flange Longitudinal Wave Guide Bridge Coupler Part C LGHT-BCPD-01 Bridge Coupler Part D LGHT-BCPA-01 Bridge Coupler Part A

Figure 6.17: Exploded view of the RF Coupling System

Item 1

Qty 1 1

2 3 4 5 6

1 2 1 1

ID Code LGHT-PMQA01 LGHT-BLLW01 LGHT-PMQP-01 LGHT-CFFL-02 LGHT-BCPA-01 LGHT-PMQS-01

Description PMQ Bellow PMQ vacuum pipe ConFlat Flange Bridge Coupler Part A PMQ Support

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Figure 6.18: Exploded view of the focusing System

Item 1 2 3 4 5

Qty 2 1 1 1 1

ID Code LGHT-LILF-01 LGHT-VLWG01 LGHT-VSPN-01 LGHT-VTWG02 LGHT-VSCF-01

Description LIL Flange Longitudinal Wave Guide Pin Transversal Wave Guide ConFlat Flange

Figure 6.19: Exploded view of the vacuum pumping port

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‘Version 2010’: Task(s) Identification As shown in Figure 6.20, the Definitive Layout accomplishes five different tasks. Given the fact that the engineering team succeeded in finding a valid brazing process in a horizontal furnace, stability was not anymore required as task. Following this layout, monitoring pickups have been installed before and after the accelerating unit and don’t affect anymore the Coupling System design.

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Figure 6.20: Tree diagram of the 3 independent systems ‘Version 2010’: Risks Analysis Similarly to what has been done for the assembly LSM30CSSUB2 on “Version 2001”, the Risks Analysis of LGHT-CPLS-01, LGHTVMPV-01 and LGHT-FOCS-01 assemblies has been performed. Costs and reliabilities for manufacturing and assembling have been evaluated. Risks Analysis of LGHT-CPLS-01 The ‫்ܥ‬ை் is around 90.0 and the ‫ܥ‬ோ௜ௌ௄ is around 11.12, so the 12.3% of ‫்ܥ‬ை் , as shown in Table 6.6.

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Figure 6.21: Risks Analysis Tree Diagram for LGHT-CPLS-01 Table 6.6: Total Cost and Risk Cost for LGHT-CPLS-01 ID Code

Description

S

O

RPN

Brazing

70+10+10 = 90

4.5%

4.05

Brazing

10

0.27%

0.03

1.2

LGHT-CPLS-01 LGHT-BCTR01/02 LGHT-BRZA-01

Brazing

34+26+10=70

4.5%

3.15

1.2.1

LGHT-BCAS-01

Brazing

24+10=34

4.5%

1.53

Provisional Assembly

8+4+4+4+4=24

4.5%

1.08

1 1.1

1.2.1(b) 1.2.1.1

LGHT-BCPA-01

BC Part A manufacturing

8

0.27%

0.02

1.2.1.2

LGHT-BCPA-01

BC Part A manufacturing

4

0.27%

0.01

1.2.1.3

LGHT-BCPC-01

BC Part C manufacturing

4

0.27%

0.01

1.2.1.4

LGHT-BCPD-01

BC Part D manufacturing

4

0.27%

0.01

1.2.1.5

LGHT-BCPD-01

BC Part D manufacturing

4

0.27%

0.01

1.2.2

LGHT-RFWG-01

7+4.5+4.5+10=26

4.5%

1.17

7

0.27%

0.02

4.5 4.5

0.27% 0.27%

0.01 0.01

1.2.2.1 1.2.2.2 1.2.2.3

Brazing Wave Guide LGHT-LNWG-01 Manufacturing LGHT-LILF-01 LIL Flange Manufacturing LGHT-LILF-01 LIL Flange Manufacturing

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11.12

Risks Analysis of LGHT-FOCS-01 and LGHT-VPMP-01 The ‫்ܥ‬ை் for the Vacuum Pumping System is around 45.2 and the ‫ܥ‬ோ௜ௌ௄ is around 3.79, (8.4% of ‫்ܥ‬ை் ) as shown in Table 6.7. The ‫்ܥ‬ை் for the Focusing System is around 10.3 and the ‫ܥ‬ோ௜ௌ௄ is around 0.93 (9.0% of ‫்ܥ‬ை் ), as shown in Table 6.8.

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Figure 6.22: Risks Analysis Tree Diagram for LGHT-FOCS-01

Figure 6.23: Risks Analysis Tree Diagram for LGHT-VPMP-01

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Table 6.7: Total Cost and Risk Cost for LGHT-VPMP-01 ID Code

Description

S

O

RPN

1

LGHT-VPMP-01

Brazing

24.4+8.3+7.5= 45.2

4.5%

2.03

1.1

LGHT-VMBD-01

2.5+0.1+5.7+7.5=15.8

4.5%

0.71

1.1.1

LGHT-VTWG-01

5.7

0.27% 0.02

1.1.2

LGHT-VSPN-01

Brazing Transversal Wave Guide RF correction Pin

0.1

0.27% 0.01

1.1.3

LGHT-VSCF-01

ConFlat Flange

2.5

0.27% 0.01

1.2

LGHT-VSWG-01

Brazing

5+4.7+4.7+7.5=21.9

4.5%

1.2.1

LGHT-LILF-01

LIL Flange

4.7

0.27% 0.01

1.2.2

LGHT-LILF-01

4.7

0.27% 0.01

1.2.3

LGHT-VLWG-01

LIL Flange Longitudinal Wave Guide

5

0.27% 0.01

0.99

3.79

Table 6.8: Total Cost and Risk Cost for LGHT-FOCS-01 ID Code

Description

S

O

RPN

1

LGHT-FOCS-01

Mounting

4.3+6= 10.3

4.5%

0.46

1.1

LGHT-PMQS-01

PMQ Support

6

4.5%

0.27

1.2

LGHT-PMQA-01

Welding

0.5+0.5+0.1+0.1+0.1+3=4.3

4.5%

0.19

1.2.1

LGHT-CFFL-02

ConFlat Flange

0.5

0.27%

0.01

1.2.2

LGHT-CFFL-02

ConFlat Flange

0.5

0.27%

0.01

1.2.3

LGHT-PMQP-01

PMQ pipe

0.1

0.27%

0.01

1.2.4

LGHT-BLLW-01

Bellow

0.1

0.27%

0.01

1.2.5

LGHT-BLLW-01

Bellow

0.1

0.27%

0.01 0.93

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6.6. Conclusion: A comparison between ‘Version 2001’ and ‘Version 2011’ Hereafter a brief resume of the results, obtained by FMEA/FMECA analyses performed on Version 2001 and Version 2010, is presented: x Applying an intensive and combined use of a tasks analysis and risk analysis, a better layout has been designed; x Tasks Analysis shall be used to identify the possible solutions: in this phase, different conditions determine different preliminary layouts; x Risks Analysis shall be used to identify the definitive solution: RPN method is a powerful tool in FMEA/FMECA in order to evaluate solutions with respect to economical and technical criteria;

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Mellace C. Mechanical optimisation of a RF coupling system

x x

Tasks and Risks Analysis can be used for both design and optimisation phases with the same purpose, which concerns the identification of the best solution; FMEA/FMECA will be certainly used for the design of the next accelerating Units.

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Figure 6.24: LIGHT First Unit proton accelerator (2010)

Figure 6.25: Accelerating Structure of LIGHT First Unit after improvements (2010)

Figure 6.26: Test facility for LIGHT First Unit in October 2010

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Bibliography 1. International Agency for Research on Cancer. Globocan Project 2008. [Online] 1.2, IARC, December 2010. http://globocan.iarc.fr/ 2. Cancer Research UK. Cancer Research UK. [Online] June 2010. http://info.cancerresearchuk.org/cancerstats/world/ 3. AIRO. Gruppo di studio sulla radioterapia con adroni. Radioterapia, Istituto Europeo di Oncologia, Associazione Italiana di Radioterapia Oncologica. Milano : s.n., 2003. p. 14 4. PTCOG. Particle Therapy Co-Operative Group. [Online] February 2011. http://ptcog.web.psi.ch/ptcentres.html 5. ADAM SA [Online] December 2010. http://www.adamgeneva.com/ 6. Poppi F. (2011), Research joins forces with industry in the fight against cancer. [Online] CERN, December 2011, http://cdsweb.cern.ch/record/1312611. BUL-NA-2010-344 7. Department of Defence - United States of America, Procedures for Performing a Failure Mode, Effects and Criticality Analysis, Military Standard, Nov 24, 1980. MILSTD-1629A. 8. SAE International (2009), Potential Failure Mode and Effects Analysis in Design (Design FMEA), Potential Failure Mode and Effects Analysis in Manufacturing and Assembly Processes (Process FMEA), The Society for Automotive Engineers, J1739 9. SAE International (2001), Recommended Failure Modes and Effects Analysis (FMEA) Practices for Non-Automobile Applications, The Society for Automotive Engineers, ARP5580 10. FMECA Process in the Concurrent Engineering (CE) Environment, The Society for Automotive Engineers, Jun 18, 1993, AIR4845 11. Pahl G., Beitz W., Feldhusen J., Grote K.H. (2007), Engineering Design: A Systematic Approach. 3rd Ed., Springer

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Mellace C. Mechanical optimisation of a RF coupling system

Topics for discussion and self-study 1. Make inventory of the main concepts and their coupling and interactions with the larger context outlined in this case study. As starting point you may use and revise/ correct/ elaborate the following visual transcript (also magnified into full-sized segments at the end of this section). Then transform the transcript into an idea network to eliminate redundancies and identify and formalise unique idea relationships. LIBO

complete technical documentation

detail design

LIGHT

embodiment

redesign

elaboration technoeconomical evaluation

embodiment design

layout & form design variants

concept

task analysis risk analysis

wishes

elaboration

redefinition as per new aim

needs

technoeconomical evaluation concept variants conceptual solution design principles function structures

evaluation & alternatives

concepts interrogated

what was missing?

function structures

new design aim: commercialised product

if new realisations emerge, added to adjustability specification independent systems

specification

sub-system

task clarification

sub-system

wishes sub-system needs

sub-system

system decomposition system original design aim: proof of feasibility

original product (LIBO)

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RF coupling system

2. What are the main relations and causalities that connect the items identified in question 1? How are they translated into processes and how effective are they? 3. Map the processes and challenges outlined in this case study onto two other case studies of your choice (also from this volume) and compare them. What conclusions do you draw? What advice can you give?

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elaboration technoeconomical evaluation concept variants conceptual solution design principles function structures

evaluation & alternatives

concepts interrogated

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sub-syst needs

original design aim: proof of feasibility

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7. Dyneema® for ballistic applications van Gorp E. (Egbert) 8 RT&D Director, Dyneema® Division, DSM, www.dsm.com

Summary The case study concerns the design and development of the Dyneema® product line and specifically its application in ballistic protection. The first part is about the yarn and the second part is about the ballistics. Why is there a difference? DSM has developed the yarn for a general market, so for all the markets being it ropes, being it nets, being it cut resistance, but also ballistics. That is where it started off with. After having the basic yarn, we moved into the applications and then it was found out that specific applications require changes to be made in the yarn, but also the value chain and approach to project management.

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7.1. Design of a polyethylene yarn The yarn has a high strength. If you consider the strength of a C-C bond then polyethylene fibres could have a very high strength something like 100 cN/dtex. The maximum strength of the fibres is however not the strength of the C-C bond. If we calculate it as the force you need to take molecules out of environment of other crystalized molecules, than we come to about 6 GPa. We are not there yet so we still have a way to go as we are now at around 4.0 GPa. Research: Discovery of a new fibre In the polymer research labs of DSM in the sixties, somebody was working on polyethylene in solution. While stirring the solution the researcher found an oriented, fibrous, strong material attached to the stirrer.

8

Chapter transcribed and edited from Mr. van Gorp’s original CSiAED presentation

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Out of interest the researchers investigated the material and found the strong fibre material, obviously produced through orientation of the molecules. However DSM had no interest in fibres the researchers as a personal interest started trying to develop a process to make these fibres. A process to continuous process these fibres from solution was developed and we called that the gel spinning process. Piet Lemstra and Paul Smith filled a patent in 1979 but they did not know what could be done with the invention. In the eighties suddenly a US company, a customer of DSM in other areas of the business, wanted to have a license. That license brought the recognition at DSM that a business value was created for high strength polyethylene fibres. In the eighties a broad market study was done to assess the market and it was found out that there were quite a number of segments where polyethylene fibres could be useful. Therefore it was decided to commercialise Dyneema® as it was branded in the meantime. This commercialization however took about 12-15 years. The principle of strong fibres is very simple, parallel well aligned structures will have a high strength. Common fibres like polyester and polypropylene have enhanced strength by drawing/stretching the fibres but are limited because of molecular interactions. Other fibres have rigid rod structure, meaning that the molecules will align under shear. Like matches that will pass parallel oriented through a funnel.

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Flexible structures like polyethylene behave like spaghetti, with long entangled molecules. By orienting these molecules via a solution, by shear through spinning and further drawing of the fibre the orientation will lead to a strong fibre (Figures 7.1 and 7.2) By orientation the polyethylene will move from quite amorphous to a highly crystalline structure, as the molecules will find their way in the crystals. The family of high performance fibres next to Dyneema® consist of aramids, like the well-known Kevlar and Twaron, but also Carbon fibres and PBO, and also e-glass fibres. For strong fibres the important parameter is the specific strength (tenacity), which is in principle the tensile strength divided by the density, and the other one is the specific modulus. Dyneema® has a very high strength and a quite high specific modulus, however lower than for some carbon fibres (Figure 7.3).

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Figure 7.1: Polyethylene: most simple polymer, but enormous potential!

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Figure 7.2: The high strength of Dyneema® is caused by extreme orientation and “extreme length” of the strong molecular chains

Figure 7.3: Dyneema® properties compared to other fibres

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melt

solution

dilute solution

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Figure 7.4: Gelspinning: Reduction of number of entanglements between very long molecules

Figure 7.5: Lowering polymer concentration reduces entanglements between molecules. Theoretical draw ratio based on random coil configuration.

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Figure 7.6: Optimisation effect of molecular weight and polymer concentration on mechanical properties The main characteristics are strength and modulus, but to make use of the fibres in applications secondary properties can be important as well. Polyethylene is a thermoplastic material which make a fibre very flexible and non-brittle, but has a melting point of somewhere around 120-140 C. As all thermoplastic materials the fibre will have creep under stress, especially at higher temperatures, it can be influenced but not reduced to zero.

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It is the combination of properties that are determining in which application a fibre finds it use. Dyneema® has found its markets and its applications. Choice of process and product There are a couple of ways to make a fibre out of polyethylene. In a melt-spinning process it is not possible to have long molecules, high molecular weight, and to get away from the spaghetti structure therefore no high strength is possible. In a high concentration solution the molecules will remain entangled which will lead to limitation in the drawability of the fibres to reach the high strength. Only in dilute solution the orientation can be made almost perfect by spinning and drawing to perfection. Drawing will give the perfection

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in parallel orientation and the high strength, at the same time the modulus will go up. Figure 7.7 from the gel spinning patent. Strength

40

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(cN/dtex)

100

30

20 50 10

0 1

10

20

30

40

50

Draw ratio (-)

1

10

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30

40

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Draw ratio (-)

Figure 7.7: Gelspinning: Ultra drawing leads to increasing properties (left) Normal (right)

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This is the theory, which has some practical consequences. The molecular weight of polyethylene must be high, up to a level commonly known as UHMW-PE, ultra high molecular weight polyethylene. It means also that melt spinning will not lead to very high strength. The ultra-drawing of the fibres leads to high strength, but has as consequence that fibres might be overstretched and are leading to yarn breakage that limits the fibre output. The practical and economical maximum draw ratio, and draw rate (the speed of drawing) determine the length of the drawing ovens, the maximum output per line and the feasible properties of the fibres. A third parameter is the low dilution of the solution to be able to reach the high drawability. A low dilution will lead to a lot of solvent to be recycled. In a gel spinning factory more solvent is being recycled than the quantity of the fibres being made. As can be seen in Figure 7.8 the solution is made in an extruder, after which the fibre is spun in a spinneret.

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Therefore a strong relation exists between the cost to produce and the performance of the fibres.

Figure 7.8: Manufacturing process of Dyneema® fibres How were the process and the products designed? From Figure 7.6 the interaction between the parameters Molecular weight, concentration and specific strength or tenacity can be seen. To determine the targeted performance of the fibres it is important to look at the competitive environment, at the moment in history being the aramid fibres with a tenacity of around 20 cN/dtex.

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An at least as good performance as the competitive fibres, having a good cost position was the target. The performance target from the beginning was 30 cN/dtex. Once having this target the parameters have to be chosen in the right way, the hardware to produce has to be chosen and developed to make it possible. The biggest hurdle to overcome is the breakage probability. This is a statistical parameter which has to be brought back to very low probability as many millions of meters of fibre have to be produced, and each breakage destroys a substantial number of meters or bobbins under production. Another important parameter which had to be dealt with was the solvent. There are a couple of solvents, split in two categories: one is

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a volatile solvent and a non-volatile solvent. This choice has a lot of consequences for the hardware of the spinning line. If you have a volatile solvent, in principle, it is easy equipment because you extrude the fibres and the solvent automatically comes out as long as the temperature is high enough to evaporate. It means also that you have to deal with an explosive environment, because almost all solvents are explosive. If you have a non-volatile solvent, then there is not a big problem with explosion, but another solvent is required, because an extraction is needed to take out that non-volatile solvent. To be honest, that extraction solvent can be again one which is explosive. DSM has chosen for a volatile solvent. That also has a big effect on how the fibre looks like, like you see in Figures 7.9 and 7.10, which are crosscuts of a multi-filament yarn very nice round filaments can be seen. The mono-filaments normally are between ten and twenty microns of single filament. With other solvents monofilaments are getting these kinds of kidney shapes, not important for the strength, but could be important for the secondary properties, which might be relevant for the application.

Volatile Solvent: Removal by evaporation + Easy equipment - Explosive environment

Non-volatile Solvent: removal by extraction + Non explosive - Additional chemical introduced

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Figure 7.9: Solvent choice: Hydrocarbons

Figure 7.10: Impact of spinning conditions on filament shape The goals for the fibre engineering were determined as: “we want to have a strong fibre, a high modulus more than 100 CN/dtex and high strength more than 20 CN/dtex, and it must be environmentally feasible and it must be economical to produce”. The direct link to performance and costs is the choice of the solvent. Our process uses a volatile solvent. The choice of the solvent is very important for the environment, important for the investment of the plant and processing of the fibre. 130

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We had to choose the molecular weight of the polyethylene beyond the existing range; DSM had to start producing another polyethylene. At that time DSM was polyethylene producer (until divestment in 2000), but we could not make this grade, a project was started at the polyolefin department to develop this grade. The choice of the drawing extend and the drawing speed, together with the concentration determines the output of the line and the cost of production, but also the ergonomy of the people that work in the plant. Every breakage means a production interruption and nasty work to be done by the operators, so breakage should be prevented. Market The first commercial plant was built in Heerlen in 1990. The first performance was 3GPa and now we are up to 4GPa in strength. In the meantime various fibre grades for various applications are developed, including a whole spectrum of yarns with different titers, or yarn thicknesses. The system was: First start a general yarn, and with the knowledge on the specific application tailored yarns are made fit to use. In this presentation an example is given for anti-ballistic applications. For ballistics the general yarn in a woven form did not perform very well, and a new form factor not being a woven material had to be developed, for that form factor a new tailored yarn was developed.

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The form factor is a product which we call Dyneema UD® -sheets; these sheets in roll form are now being produced in all our plants in Heerlen (NL) and Greenville (USA). To produce the sheets we use a fibre that is produced in our fibre plants at the same locations. Because the anti- ballistics market or much better said the Life Protection market, is much more located in the USA the biggest production of these products takes place in Greenville. Next to the Life Protection market also products and fibres have been developed for other markets like mooring ropes, cut-protective gloves, lifting slings, fishery and more important aquaculture for fishing, cargo nets, sails and cargo containers for airplanes

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Figure 7.11. Ballistics: Personal protection

Figure 7.12: Ballistics: Vehicle Protection (Spall liner in the XA-188 APC Armoured Wheeled Vehicle)

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7.2. Design of UD product for ballistic applications Fundamentals For Dyneema® ballistics means ballistic protection; the products are designed to protect against bullets and other projectiles, and to protect people. Helmets vests and protection plates which are inside a vest are designed to protect against ammunition from handguns, rifles and automatic guns dependent on specifications set. The products can be split in products that are used as a composite, pressed material (like a helmet or an armour plate) and a stack of connected soft layers or sheets like in a protective vest. Especially for vehicles the armour plates can have a high weight, even some 150 kilos per square meter to protect against high level treats like mines and high explosives. The fundamentals of ballistics: Why does it work with fibres? In ballistics the kinetic energy of the bullet has to be stopped and to do that the energy has to be dissipated in one way or another.

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Even for a small pistol with a 9 mm bullet the kinetic energy is easily around 700 J. If all that energy had to go into the material in the place of impact the temperature of the material would increase with 500 degrees. Therefore initially competitive materials would not see polyethylene as a competitive ballistic material: ‘it will never work, because it will melt’. This proved to be not true, which means that the stopping mechanism is different from the initial idea. Part of the energy, as can be seen in Figure 7.13, is taken up by the bullet as can be seen from the deformation after impact. This is a nine millimetre bullet; there is a lot of energy absorbed in the bullet. Deformation of the bullet depends a lot on the type of bullet. A full metal jacketed lead bullet like the one in Figure 7.13 is quite deformable. Bullet designers design the bullets to get the required reaction, protective materials need to cope with highly penetrative, less deformable as well as much more deformable bullets.

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Figure 7.13: Not all energy needs to be dissipated by the protective material also the bullet absorbs a lot of energy by deformation How do the fibres stop a bullet? This is governed by the so-called Cunniff equation (Cunniff & Auerbach, 2002): U*

V utsH f 2U

E

U

*

The stopping energy U is governed by the ratio of the ultimate tensile strength V uts divided by density U (in fibre terminology this is the tenacity of the yarn in cN/dtex), the square root of the specific E modulus in CN/dtex and the elongation to breakage H f .

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U

For a yarn this means a high strength and a high elongation to break, which can be seen as the energy to break of the yarn, or the area under the stress-strain curve for calculation purposes. But the formula says also that there is a component linked to the high modulus. This component comes from the amount of material that is involved in the impact. If only the material at the impact point were to be involved not enough energy could be taken up. Through the shockwaves in the yarn the impact moves through the yarn and more yarn away from the impact point is taking up energy as can be seen in the high speed camera picture 7.14, where the bulge of the material can be seen that is impacted by the bullet. The shock waves are moving with a speed linear to the square root of the modulus.

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The energy taken up in impact through the Cunniff formula can be seen as the energy to break of the material multiplied by the amount of material involved, as it is spreads out from the point of impact through the shock waves in the material. Therefore much more material is involved in the impact than one would expect. This is all with the provision that the shockwaves are not hindered. In fact, if you shoot a fabric or any ballistic article it is not only that the yarn will break at the point of impact, which would absorb very little energy. What happens is that a shock wave propagates through the yarn and is spreading out, carrying and thus eventually dissipating much more energy. That is visible in Figure 7.14, where clearly the shock and corresponding affected area is not only the size of the bullet, but is a whole sphere around it, which is participating in the protective forces of the fibres. So you are involving much more material than the one that you would expect.

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Figure 7.14: High speed video snapshots of shock wave Practical application With the start of the development of the ballistic products in the 80ies the state-of-the-art was making fabrics from strong fibres like Kevlar or Twaron or even Nylon. These fabrics produced the sheets that could be confectioned into vest and cut into sheets for composite forms like helmets. Unfortunately making fabrics and stacking them to ballistic protective products did not seem to work well for Dyneema®.

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Initially this was not well understood as the properties of the yarn were well in line for a good ballistic performance, which meant that the form factor ” fabrics” did not work for Dyneema®. It was concluded, after verifying the results and the observation of the materials after impact that in the form factor fabrics like in Figure 7.15 that Dyneema® did not involve enough material in the stopping action. There are two reasons to understand this phenomenon: 1. The fibres of Dyneema® have a very low friction coefficient, which makes them very slippery; this means that in a fabric the fibres are moved away by the bullet in such a way that less yarns are broken after impact than should be broken given the diameter of the bullet. The hole is smaller than the diameter of the bullet, see Figure 7.16. 2. The 2nd reason is the reflection of the shockwaves because of the crossings of the weft and warp in the fabric, even more so if fabric is made very tight to prevent slipping. Hindering the shock waves from propagating results in fewer fibres being involved in the impact.

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An alternative ballistic product form was designed, preventing both the crossovers and the slip of the fibres, still having the cross-plied function to make sure the shockwave is moving in both directions to form the impact bulge. This material we called Dyneema UD® (UniDirectional). It comprises a unidirectional web of fibres which is made into a composite sheet using a suitable matrix, and a same second layer which has a 90 degree direction versus the first layer, as shown in Figure 7.17. This way a cross-plied UD material has been designed that can be used in multi-layered structures. The first UD products produced by DSM Dyneema were made on a continuous roll of material and had 4 layers per sheet.

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Figure 7.15: Fibres, woven in a fabric, have a reduced performance due to a slowdown of the shock wave. State of the art with competing fibres does not work.

Figure 7.16: Ultra high molecular weight Polyethylene is often used in applications where low friction is required. Fibres are partly pushed away instead of being broken, fibres have too low friction

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Figure 7.17: By producing a UD sheet most of the bending points can be avoided After UD development, product and process development still had to be done. First of all, the production process to make the parallel and the cross plied fibres was not available in the market. The task of making it a continuous material, as opposed to single sheets, was an ambitious target to be met in a continuous, automated process.

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We also found out that different bullets required different constructions of UD, and even different fibres to start off with. It is understandable that various matrices were required as the requirements for a stacked material like for vests is quite different from the requirements for composite part like helmets and armour plates . The matrix serves in the composite part also as the matrix to make it a structural part. Less understandable and much less obvious is the construction of the UD. How many monofilaments per layer, how many layers per sheet: two layers, three layers, four layers, or even more. These variations with the performance of the fibre itself do determine the ballistic performance, as structures are having an effect on the ballistic performance of Dyneema UD® dependent on the type of bullet. In this process of UD development DSM a lot of research power inside the company and cooperate staff was used, but to speed up the process we did not try to reinvent the wheel, and where possible and available a license was taken. Developing Dyneema UD® and producing it ourselves resulted in DSM Dyneema selling further down the value chain, not as a fibre producer to a weaving company, but to vest, helmet and armour plate manufacturers but even with users like armies and police forces.

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By not needing to sell to weaving companies a different value chain was created, more direct to the users. Compared to the existing market structure this created a complete different competitive environment, a challenge for the marketing and sales department. The need for an organised project organisation becomes very much apparent. A structured process, also called a stage gate, divides the project in phases not only in the idea generation, feasibility and the technical development, but also in the commercial development and product launch and the implementation of the project. A final project closure only takes places after an evaluation process judging the success of the project, the resources and the timing. The achieved commercial targets, based on the technical achievements, are a main criterion. After a successful project a new project can be started like for the life protection market a specific vests and UD for a specific riffle used in

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Asia or vehicle armour to protect against road-side bombs in the Afghanistan war (Figure 7.18). For technical people it is good to understand that technical success is not the end of the story, but that mostly quite some marketing and sales efforts are required to get the success. Therefore in professional companies like DSM, project management is common practise nowadays to steer and manage the projects being it plant extension, internal processes, or product development and introduction projects. We have been successful in our goals to produce products that do protect people and that is where the DSM Dyneema mission for Life Protection comes from: ‘With you when it matters’.

Figure 7.18: Armoured vehicle tested against roadside bomb blast

Bibliography

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Cunniff P.M., Auerbach M.A. (2002), 23rd Army Science Conference, Assistant Secretary of the Army (Acquisition, Logistics, and Technology), Orlando, FL, December 2002

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Topics for discussion and self-study

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performance

choices

cause

t an duc

application requirements/ constraints

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process physical properties

ergonomy

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1. Make inventory of the main concepts and their coupling and interactions with the larger context outlined in this case study. As starting point you may use and revise/ correct/ elaborate the following visual transcript (also magnified into full-sized segments at the end of this section). Then transform the transcript into an idea network to eliminate redundancies and identify and formalise unique idea relationships.

commercial activity

technical development

2. What are the main relations and causalities that connect the items identified in question 1? How are they translated into processes and how effective are they? 3. Map the processes and challenges outlined in this case study onto two other case studies of your choice (also from this volume) and compare them. What conclusions do you draw? What advice can you give?

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van Gorp E. Dyneema® for ballistic applications

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er

for patent ffo or fiffibre ibre r and manufacturing manufa acturing process proce ess

manufacturing process for f r fo continuous contitinuous production pro r ductiton of fiffibres ibre r s

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technical development

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joint venture partnership for not-core activities (with textile manufacturer)

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recognition extern r al external i tere in r st, t interest, lillicensing censin i g

restructuring the market

commercial activity

technical evelopment

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Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved. doi:10.3233/978-1-61499-242-4-144

8. From raindrop to radar and from needs to technology Russchenberg H. (Herman)9 Head of IRCTR, Delft University of Technology Netherlands, www.tudelft.nl

Summary The presentation narrated the development of advanced radars for weather monitoring. It closely traces the cause-and-effect relationships that drive advanced engineering design from societal problems to science to design and product development to address the original societal problems. The case study shows how engineering design works on the basis of scientific models, specially developed to analyse and parameterise the phenomena employed in the design.

8.1. Introductory context: Climate and the weather

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Good afternoon, my name is Herman Russchenberg. I am with TU Delft. This presentation has a big difference with respect to the other presentations, because when we design or develop something, we do not do a market survey. Instead we have a scientific problem that we want to solve. In our case the scientific problem is linked to climate change and from there on we start to develop instrumentation to do measurements or to solve the problem. As you all know our world is slowly warming up. Some people do not believe it. Some do believe it in the end, because it is really happening. This is causing all sorts of challenges for us. At the same time what is also happening right now is that most of the world’s population is moving into the city. More than the half of the world population is living in the city right know and this will increase. These two things together will propose enormous challenges for us for the future: For instance, you get prone to severe weather. Every 9

Chapter transcribed and edited from Prof. Russchenberg’s original CSiAED presentation

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time when I give a presentation I mention whether I can give examples of recent events. Also this week we have resent events in Belgium and the south of Holland with extreme rain forming flooding. Basically this is happening every week. Somewhere in the world there is an extreme weather event and this will increase with climate change. At the same time what also is happening is that when you move people into the cities, you get problems with their infrastructure. This is a nice case you all know, traffic congestion: if you commute every day you are stuck in traffic jams somewhere. Cities get prone to heat. You all know that in the city it is warmer than on the country side, but this will increase. Calculations were done for cities like London on a normal summer day in the future climate: it can then be nine degrees warmer than outside London. This has an enormous impact on public health. If you look at the mortality rates, they go up drastically if the temperature goes above fifty degrees. And I talk about nine degrees in the city, which will lead to an enormous mortality rate in the big cities and everybody is going to the city, so it is amplifying itself. All these developments are going on right now and they will increase. This means that we have to do something about it, because when you can say ‘can get prone to’, it can happen, but at the same time it is still up to us to do something about it. Think of clever techniques, clever technologies and clever policies or whatever you need to do to change this. The challenge is then to make cities a nicer place to live, because everybody is going there in summer time and winter time.

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My talk for today will be about one of the things you have to do to make cities a good place to live, in the context of severe weather: how to deal with the extreme rain fall events that we can expect in the future and what sort of techniques we have to develop to get there?

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Figure 8.1: Climate scenarios by IPCC Figure 8.1 is a famous graph taken from the IPCC, the Intergovernmental Panel for Climate Change. If you read the newspaper you know what IPCC is, because nobody believes them anymore, but the work they do is very valuable and it still holds. What they did is, they took all the climate models around and they said to them: ‘well before I believe you, you have to be able to reproduce the climate of the past’. What you see here, is that they calculated the global temperatures the climate of the past. The solid line is the measurement and beyond the vertical mark is the range of predictions of world climate models. If you do this well, you can use your model to predict what will happen in the future. Of course, in the future nobody knows what will happen. We have to make some assumptions about world population, growth, economic growth and changes in Europe and China and India. All sorts of futures and scenarios are used and you can produce this range of future climate a hundred years from now and you can see the range is enormous. Depending on what you can expect over there.

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Figure 8.2: Temperature map of the Netherlands What can we expect in the Netherlands? Usually Figure 8.2 is a nice picture to show, but this is the Netherlands right now and what we can expect here, is that the climate of France is slowly moving up. So we get the French climate. Everybody says: ‘hey, that is nice. Can it come tomorrow please?’. Well, do not be that happy, because if this happens, we get a lot of changes in nature, but that is not the topic for today. What you also get is rainfall. What will happen if the climate changes? You get high temperatures, high temperatures leads to more water vapour, more water vapour can lead to more clouds and more clouds can lead to more rainfall. Basically what you already know from the tropics, the rainfalls from the tropics are much more severe than they are over here, is slowly moving north and southwards. This also means that the climate changes here and it gets warmer here and then we get more intense rainstorms. In the south of Europe it is already a big problem, in France it is a big problem, but we get the same issues over here. Together with the notion that the world population is moving into the cities, where it even more difficult to

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Russchenberg H. From raindrop to radar and from needs to technology

cope with all this water, you can see what the problem will be. It will be an enormous problem. Already in a city like Rotterdam, they have multimillion damages every year whenever there is a thunderstorm, because the sewer systems cannot cope with the surplus of water. You get flooding on the streets, cellars get flooded and damaged. We have to know how much rain we can expect and then we can be better prepared with prediction of the rainstorms, but can we really say that for tomorrow at three o’clock we have a huge rain event on the market square in Delft? That is the sort of accuracy you need. Right now it is not more accurate than: ‘tomorrow there is a change at rain somewhere in the west or the north of the country, it can be in the morning or in the afternoon’. That is the accuracy of today. That is not good enough in view of the change the climate. Already if you look at the measurements and you take the rain fall measurements of the last hundred years, there is an increase of one hundred per cent. So the trend has already started. We get more rainfall. This is a sort of event that we can expect more and more the coming decades. These are the types of events which are also dangers because a huge part of the rainfall, also a huge amount of wind gust and strong winds that can blow cars away from the high way: there is a lot of damage you can get from this. Then in cities, when you have all these situations, how can you improve this? You need better information. Everybody who is managing water in cities or traffic in cities needs up-to-date information, but this information is not available yet, because most of the weather measurements and climate measurements are done in country sides, because in cities they are not reliable. It is not representative for larger areas. So we have to do these measurements with high-resolution. At street level for instance, you have to take all these data. You have to combine these with clever high-resolution weather models for predictions. That is the way that it will move into the future. That will combine all these things together.

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Figure 8.3: Effects of climate change and resulting needs

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8.2. What radar measures The basic component of monitoring this is the radar. Radars are very simple instrument. They transmit a signal up and then when the signal gets in the atmosphere it hits a raindrop and then part of the signal goes down again. All you have to do is receive the signal and analyse the signal to get information about the rain. That is a basic principle. But then of course the question is: how do you design such a radar system and what is the specification of the radar system that you need for urban water management, for instance, for the future climate? It gets a bit more complicated. What do you need to know then if you talk about radar design? You have to know where the rain is. That is simple. You also have to know the intensity of the rain. How much rain is falling actually? That is already more complicated. For predictions you also have to know, how will the rain develop? That is even more complicated. The location of the rainstorm is something one of the first things they managed to calculate after the Second World War. It is simple: They saw that this could be done. At that time they also showed that radar can be used to study rainfall. Ever since then, they are trying to solve this part. So how can we link the radar reflectivity, the radar

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reflection, to the intensity of the rain itself? It is still a big problem. I will tell you later why this is.

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Figure 8.4: Location of a rain storm First, the location of the rain storm. All that the radar does is, you transmit a pulse in this direction, it hits the object here and part of it will be reflected backwards. Then you know the speed of light so you know how fast the radar ray moves and then you can derive the distance from here to there by the simple formulation shown in Figure 8.4. It is an easy approach. What you need there is you need proper signal generation, because the arrow in the figure represents all sorts of wave forms: it can be a rectangular pulse, can be continuous signal with a complex modulation in whatever you need that requires signal processing. For the direction where the rain is coming from, you take an antenna and you slowly rotate the antenna. It needs clever antenna design. 150

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When you look at your wireless, your mobile phone or whatever, there is an antenna around you, and they all need very clever designs, because they have to be designed for a particular application. The antenna most people know is, for instance a dipole, looks like the bottom right of Figure 8.4, but in only measures and distributes energy in a circle. That means that if the rain is here or it would be there, you cannot discriminate where it is coming from. It could be anywhere. So you have to change the antenna in such way that you focus the energy beam of the antenna that it only comes from one direction or transmits in one direction and then this has to rotate over the full circle. The question then is: how much should I focus it? How narrow should a beam be and how far should it rotate? That choice can only be answered when we have enough understanding of the physics of the rain itself. The measurements you see have to be representative for the rain that you want to measure. If it is too narrow, there is a big chance that you will not get hit by a raindrop at all. If it is too wide, I suppose as wide as the whole auditorium here, the chance is big that because of too much variability and too much inhomogeneity in the rain you cannot make the right interpretation of your data. You have to find an optimum beam width linked to what you know about the spatial patterns of the rain that you want to study. You need atmospheric science before you can make a clever antenna design. You have to be able to take one step beyond your own engineering discipline and talk to a meteorologist and become one yourself in the end before you can make a proper design here.

Figure 8.5: Accuracy of location of a rainstorm

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Then something else, rain measurements are basically coming down to counting the number of droplets. You use the radar to count how many raindrops you have in the rain storm. That means you have to work with a signal which can collect all these droplets. This is done by manipulating for instance a pulse shape and width, as shown in Figure 8.5. And that comes down to getting enough droplets into your volume that produce enough energy that you radar can measure it and at the same time you should be able in your signal pro-analyses afterwards to say how many droplets you have over there. That requires a clever understanding of the scattering process itself. How does a radar wave scattered by the raindrops? What is happening when a radar wave, electromagnetic wave, hits a rain drop? What is happening inside the raindrop with the energy? How is the energy transported back again? Today you see that it is not just a technical discipline but also a physical discipline. You have to combine all these disciplines together. In the end you talk about signal generation and you talk about processing. What to do with the data to separate all these individual drops and come up with the answer with how many droplets you have? If you wrap this up you get what they call the radar equation. It looks like this, it is very simple as you can see it only needs some explanation, there is an antenna over here, what you do is you transmit a certain power peak. The antenna focuses the energy into certain directions which is quantified by the term J over there. It transmits the signal to what you want to measure over here. Distances are long and then it is scattered back into another direction wherever you put the receiver antenna, it can be at same location and also a different location.

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Figure 8.6: The radar model In the end what you get is an equation like what is shown in Figure 8.6: it is called the radar equation, it links the received power to transmit power, antenna properties the wave length of choice and the distance that you have. It also links directly to your system design. That equation is the basis for your system design. What you see here all these terms, the system terms, can be lumped into one constant. What you have to do is to play with the transmit power. How much power you have to transmit to get enough signals back? And antenna design. These are two different disciplines. Generation of energy, which I talk about here, is something else than antenna design; they are also completely different communities. The antenna community is a different community than a microwave community. Here, the term K that you see, is linked to the material of the scattering particles. It sounds a bit abstract, but in case of rain it just means water. It can also be snow, it can be ice. It can be anything else like dust in the atmosphere. It means you have to know the electromagnetic properties of the particle that you want to measures. This is physics again and methodology which is coming in there.

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Finally the term Z is the term you want to measure. That is linked to the number of particles and the size of particles. What you see is, if you want to develop a radar system, you really have to look into this. Question: what is the definition of rainfall rate?

Answer:

R

the volume of rain water collected per unit of area and per unit of time

³ N (D)v(D)Vol (D)dD Fall speed of raindrop

Volume of raindrop

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Dropsize distribution

Figure 8.7: Intensity of rainstorm (photo sources: everythingweather.com, Wikipedia.com) Metrology, electromagnetism, material properties and you have to look into engineering disciplines. How do you do this? everythingweather.com has a nice visualisation of the whole thing: A radar is transmitting a wave towards the clouds. It hits the storm and a part of the signal is transferred backwards. Zooming in a bit on what is happening in the cloud itself, you can see that the wave hits, every particle individually and every particle distributes a part of the

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energy back to the system. Somehow you know that the receiver power is related to the rain fall rate. How much rainfall is falling there? How can you link the voltage that you measure at the receiver to the rainfall rates, how much rain do we have in millimetres per hour on the ground? Well, like I said in the beginning, that question has been asked in the last fifty years, sixty years already, and still has not been solved yet. That is because of the randomness of the atmosphere, the stochastic properties of the atmosphere, a huge viability that you have in rain fall types, cloud types and regional difference: rain fall here is different from the rainfall from the south of France or in Indonesia or China. So there is not a single solution for this. But how do you usually deal with the problem? First of all when you talk about rainfall rate you start with the definition of rainfall rate. What is it? How do we approach it? Figure 8.7 shows the definition; it simply says that it is the amount of water that passes through the surface or volume per unit of time. It depends on the drop size distribution, which is the number of droplets that you have in a volume of a particular size, the fall speed of the droplets, how fast they fall and the volume of droplets. Here again you see the metrology coming in. The full speed of the droplets is something we know from a wind tunnel experiments, additional experiments we did in the laboratory and looked at the relationship between full speed of particles, if you release a particle like this, how far does it fall and then you can see the larger the droplet the faster it will fall, but you need this relationship. And you have the number, which is the drop size distribution. We know this, it is coming from models, and this is straight forward, a geometrical function. So the question which is left is, if you want to calculate the rain intensity, what is the drop size distribution? Then again is when the radar comes in. The radar has to be designed specifically to measurer the drop size distribution. How do you do this then? The same principle, first you describe what happens by one particle and then you can get complex scattering theories. It does not have to be complex; you can make a simple assumption, but in general occasions it is a complex scattering theory. Then you estimate the scattering by the total ensemble of particles and then you calculate what the radar would see. Then you compare this with what the radar has seen. You tune a bit with the parameters and get the right value. In the end what you get is a simple relationship, this is what the radar will see and this is the relationship

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with the drop size distribution. It looks very simple and it is very simple and therefore it is not true. Usually what you see here is the best you can do with simple radar types. It assumes implicitly that the droplets are spherical. What do you think the shape of a raindrop is? [audience answers] Egg shape, oval. It is different. First of all we have ice crystals in the atmosphere. They have all kinds of shapes and they can occur in many different particles, like Hail and then we have the answer to the question, raindrops.

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Raindrops look like this what you see at the bottom left of Figure 8.7. The image you had of this egg shape is what you see when it falls out of a crane or simply due to adhesion to a fixed object up there. When you release a raindrop in the atmosphere it starts off as a sphere. When it falls you get air resistance and it will flatten at the bottom. This is the relationship: the larger the droplet is the more flat it will become. The small raindrops are spherical because the air resistance is not that much, but big raindrops have this shape. That is important, because it means first that this relationship I showed you at the beginning is not accurate enough, because I assumes spherical raindrops. What only holds is that that there is a relationship between the shape and the size. It means if you are able to measure the shape of a particle, you are also able to measure the size of the particle: Close to what you want to have. How can we do this? For this again you dive a bit into the electromagnetic theory and you look at how an electromagnetic wave looks like. One thing is important and that is a polarization of the wave: You can play with it. You can use the polarization of the wave to measure the shape of an object. You have to believe me, because it is too complex to explain. But a shape of an object is as shown in the bottom right of Figure 8.7 and I use vertical polarization, I get a strong return. If I use a horizontal orientation I get a week return. So it means if I play with polarisation, I change from vertical to horizontal and I do this in clever ways, I can scan the shape of particles in the atmosphere.

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Figure 8.8: System concept

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What you can do then, you can implement it all in one system and what you basically get is a layout like in Figure 8.8. The antennas, which you have over here, transmit and receive in a chain that you have over there, the antennas that you have that are needed for localization of the object, localization of the rainstorm. You need to guess what type of rain, or hydrometeor as it is called in general terms, you are dealing with. Is it rain, ice, snow or whatever? In here in the antennas, you usually build a polarization switch so you can play with the polarisation. On the left all the signals are leaving the transmit-receiver chain: you go into the signal processing part of the system and you look at the system processing itself so it is the first processing you need to enhance the data noise removal, removal of objects that you do not want to see. Then the important step is how to get the information that you want of the data out of the signal and then finally the visualization.

Figure 8.9: Hydrometeor visualisations

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You all know about the weather images at the news every evening there you see them. Figure 8.9 is an example of the visualization. In the end you need much better tools to get high-resolution forecasts and maybe you have to go to three-dimensional type or virtually type of visualisation of this. I showed you an example of what you can achieve with the radar. This is what you see over here a rain storm passing over the Netherlands. With the radar, with all the tricks in there, the polarisation change, clever processing and so forth. You can get this sort of information out of it. You can identify the regions in there where you have eyes or mixed face clouds, and mixed face means water and ice in the same volume. You can identify regions where you have a melting snow and ice falls down, it melts over here and this is called the melting layer. You can identify the region with the rain itself, identify where we have very light rain called grizzle, which is a different type of rainfall and you can measure identify regions where we have echo’s due to turbulence in the atmosphere. All this is in the end what you need to get better forecasts of the rain itself. Because the rain on the ground what you experience here is coming from a loft and as you can see it is not falling down as rain. There is a whole physical process behind it is rain that you feel on the ground. For proper predictions you have to understand and you have to measure this process.

Figure 8.10: Two radar designs developed at the IRCTR

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8.3. Radar designs The rainfall radars we have developed at the laboratory here are shown in Figure 8.10. One of them sits on a tower of two hundred and thirty meters high. It is near Lopik, which is seventy kilometres away from here. There we have one of the most advanced observatories for the atmosphere in the world and this is a system we developed on top of the tower, which was a challenge in itself to get up there. It took two weeks to get it there because we needed to wait for nice weather. There should be no wind. The system is developed such that you had to put it there and there were some screws and screw holes that fit exactly. And it could only be done with absence of wind, no wind at all and only nice weather. Two weeks to get this weather, I think five hours or so to position it correctly and put it over there. This system is also developed in-house. You see these large shrouds? They are necessary because we have two antennas and you want to avoid that a transmit signal from one antenna feeds in to the other antenna directly because you get too much signal and you get over steering of your receiver. That is why we have the shrouds over there. You can also see three elements in here. They are those we can switch fast within a millisecond from one looking direction into the other and you can switch back and forward. You can make very rapid scans of the atmosphere. This here is a more traditional antenna type, it rotates once a minute and scans the whole area. The one on the right side is a real research radar which is also used at the field campaigns on other places; the next campaign will be in the south of France in 2012 for severe weather studies and this is a research radar that we built for grizzle type of studies, light rain because they are very important for the climate system. This is also a system which is now been considered as a proto type for the city Rotterdam. Like I told you in the beginning, urban rain falls are getting important and Rotterdam has decided to at least allocate funding to buy such a system, put it on one of the high buildings in the centre of the city and make rain fall maps over the city itself with high-resolution on a street scale. So what started as a scientific project, we needed to solve some scientific problems, is now also ending up in somewhere else in society in cities for practical use. Also the province of south-Holland is participating in this project in Rotterdam because they have the long term vision, where they give every city in the Randstad such radar. In twenty years or so, the

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Randstand area will grow and more population will be there, more sensitive to severe weather situations so you need proper information.

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Figure 8.11: Weather radar measurement (MPI) So you can see what started as a scientific question and now a laboratory is growing into a large societal network. An example of the system here is the high resolution data and Figure 8.11 shows three meters resolution data of rainfall distribution over the area in Kabao in Lopik and here is the corresponding wind field that you have with this. If you compare this with the standard weather radar, it is what you see in Figure 8.12: the standard weather radar that you know from the news has a resolution of one kilometre. That means that every value contains all the rain in a square of one by one kilometre. If you walk on the street during a rainfall, look carefully and you will see the variability in this one by one kilometre, but this number is not representative at all. Here we have done the same measurement with our radar for thirty meters resolution. That is much more accurate. Especially if you look at parts like this, you see that this radar picks up this detail here much better than the large system over here but this look like noise, but here we can see there is really something developing there. On that day this particular small event also develop into a rain storm itself. Pick up moisture from the ground and started to grow. It is not something you will see, or you recognise easily with standard weather radars. This is one of the first examples that showed that you need high-resolution systems to get more accurate data. This brings me to the end of the presentation.

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Figure 8.12: High-resolution weather observations

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8.4. The role of the engineer What is the role of the engineer now in such a process? It is a multidisciplinary problem we are dealing with. First of all, system design, but this is never enough if it stays only at the level of the device itself. You have to consider the bigger system. You always have to talk or consider atmospheric sciences in this and you have to talk to the end user to this. If we do not do this then we can never make a proper system design. If you want to see more detail, the end user here is needed for the interpretation of the data, because as an engineer, when you develop a radar system, we usually think in terms of what did I put in and how much voltage do I get back, but that is not what people want to have. People want to see what does it mean? What does it represent? What is this voltage that you measure? For this you always have to communicate with the end user of the data. They can help you with this. Here this scattering process, when you stand out the radar wave and it hits something in nature like a rain cloud, you have to consider again what the users can give you as input in this case atmospheric scientist, a metrologies, they can tell you what statistical properties of the medium is which you want to measure, which means how many raindrops do you have? And what is the statistical behaviour of this? That translates directly into statistical properties of the signal that you will get. Also directly into the signal processing that you have to develop. It is very important to have all these groups involved into the design of the system like this. And that is where I want to end my topic with. 161

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Thank you for your attention.

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Figure 8.13: Systems model of radar design

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Topics for discussion and self-study 1. Make inventory of the main concepts and their coupling and interactions with the larger context outlined in this case study. As starting point you may use and revise/ correct/ elaborate the following visual transcript (also magnified into full-sized segments at the end of this section). Then transform the transcript into an idea network to eliminate redundancies and identify and formalise unique idea relationships. modelling is means of understanding & reproducing past, present and future

wish: increase prediction accuracy

mappings (i.e. similar weather patterns in tropics) direct measurements (i.e. rain droplet shape)

hypotheses (to be tested & verified later, i.e. population growth rate) experience

uncertainty: predicted states

approximations of the truth (i.e. raindrop shape)

validate (reproduce climate from the past)

evaluate and analyse

need: develop instrumentations

earth (global climate) model

cause-andeffect

ed e ne do w what know? to

assumptions on influencing factors

region (local climate)

design choices to best meet requirements (optimisation)

predict future

need: do measurements

breakdown of requirements conceptual design

deployment

understanding of the physical multiple disciplines phenomenon needed to inform choices (rain)

model modelling drives design choices

multi-scale wish: solve scientific problem

cloud

embodiment & detail design

particle policy forming

technical solutions

wish: solve societal problem

societal relevance

sub-phenomenon (clouds and natural airborne water phenomenon droplets) (climate change)

enabling technology/ know-how (radar)

radar wave scattering by droplets

atmospheric sciences system design

role of the engineer consideration of end user needed for interpretation of data

effect on society

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societal circumstances (population moving to cities)

2. What are the main relations and causalities that connect the items identified in question 1? How are they translated into processes and how effective are they? 3. Map the processes and challenges outlined in this case study onto two other case studies of your choice (also from this volume) and compare them. What conclusions do you draw? What advice can you give?

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Russchenberg H. From raindrop to radar and from needs to technology

model of und repro prese

wish: increase prediction accuracy

mappings (i.e. s weather patter tropics)

hypotheses (to be tested & verified later, i.e. population growth rate) experience

uncertainty: predicted states

approximations of the truth (i.e. raindrop shape)

predict future assumptions on influencing factors

validate (reproduce climate from the past)

need: do measurements

model multi-scale

wish: solve scientific problem

cloud particle policy forming

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evalu an

need: develop instrumentations

earth (global climate) region (local climate)

cause-andeffect

technical solutions

wish: solve societal problem

societal relevance

sub-phe (clou natural airborn phenomenon drop (climate change)

effect on society societal circumstances (population moving to cities)

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Russchenberg H. From raindrop to radar and from needs to technology

modelling is means of understanding & reproducing past, present and future

mappings (i.e. similar weather patterns in tropics) direct measurements (i.e. rain droplet shape) experience

use-andeffect

design choices to best meet requirements (optimisation)

evaluate and analyse

ed e ne do w w h a t know? to

need: develop nstrumentations

breakdown of requirements

embodiment & detail design

conceptual design

deployment

understanding of the physical multiple disciplines phenomenon needed to inform choices (rain)

model modelling drives design choices

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sub-phenomenon (clouds and tural airborne water omenon droplets) e change)

enabling technology/ know-how (radar)

atmospheric sciences system design

radar wave scattering by droplets

role of the engineer consideration of end user needed for interpretation of data

on ety circumstances moving to cities)

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Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved. doi:10.3233/978-1-61499-242-4-166

9. Océ VarioPrint 6000 platform design Albers A. (Ton)

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Lead Designer, Océ-Canon, Netherlands, www.oce.com

Océ Technologies is a leading printer company in Europe with 1500 people working on research and development worldwide, and is since 2011 part of Canon. One of its key developments is the VarioPrint 6000 system (Figure 9.1). This printing system is the fastest cut sheet printer in the world, able to print about 320 images per minute. The VarioPrint systems are mostly placed in large print facilities, for instance for insurance companies in order to print insurance documents. World’s largest internet book companies use several VarioPrint systems to print books-on-demand, which is used to reduce their stock. Productive printing systems like this should be kept running to use their productivity to the full extent. The system produces large numbers of printed output that is controlled by the highly sophisticated queue management. The predictable throughput allows the operator to schedule when his presence is needed for instance to load and unload paper from the system. Various paper modules and finishers can be added to the system in order to maintain the paper flow. A special feature of this printer is the one-pass duplex design, meaning both sides of the paper can be printed simultaneously in one run. This design and its issues are discussed in this report.

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Figure 9.1: VarioPrint 6000 printing system

9.1. History

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The core technology for the VarioPrint series was already used in earlier Océ products, Figure 9.2 shows a digital copier from the nineties. The copying speed was 65 pages per minute (ppm). The revolutionary feature of the system was the possibility of using a network kit that enabled printing. Most copiers had the network abilities, but were mainly used as excellent copiers since it took a long time before the users were used to print on those machines.

Figure 9.2: Digital copier Océ 3165 167

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Ten years later, the machine evolved to the new model (Figure 9.3) at the speed of 85 pages per minute. The description “printer” became more common for such machines. These systems required larger capacity for the paper modules because of their higher printing speed.

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Figure 9.3: Océ 2110 Printer/copier Océ continued to increase the print speed steadily. In the 1990s it was 65 ppm, growing to 85 ppm in ten years. The progress kept on up to 110 ppm in 2006. Their biggest competitor, Xerox, launched a 180 ppm printer, which was the highest speed at that time. An attempt to achieve that speed would take some years to go, and by that time Xerox would probably release a 200-plus ppm printer. The Outcome of market research revealed an interesting point about the duplex printers. These type of printers enable customers to print on both sides of a paper. This is firstly very cost effective because the cost of paper is dominant in the cost of a print, so to reduce the cost, a simple solution is to use both sides. Secondly it is more environmental friendly because duplex prints have a smaller ecological footprint. Océ discovered that the share of duplex prints of the total print volume was already larger than 70%, and steadily increasing. The increasing duplex volume brought Océ to an alternative solution, to

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deploy two engines and print both sides on one run. The printing technology that was used in the earlier machines, called “contact transfer”, enabled such a design, and would be much harder to achieve for printing technologies used by competitors. They doubled the engine, installed it in mirrored position and as simple as that they had a concept for a double-speed model.

9.2. Contact transfer

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The schematic lay-out of the 85 ppm machine is demonstrated in Figure 9.4. The paper path is depicted in red. Sheets start from the paper module at the right, go through the process modules on the left following the arrows. When the image is printed on the paper, it returns on the top path to the finisher where it is stacked or stacked/stapled.

Figure 9.4: Contact transfer example layout In Figure 9.5, the left process modules from Figure 9.4 are magnified, which are respectively the photoconductor unit and the fuse unit. The photoconductor belt (green) is guided by several rollers (green circles) and has a photoconductive layer. This layer functions as an isolator in darkness, and becomes a conductor when it is exposed to light. The photoconductor is transported and passes the charging unit.

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The charging unit puts an electric charge on the photoconductor. In darkness, the charge stays on the isolator. The next unit is the optical print head that encompasses about 7,000 very tiny LEDs to shine light on the photoconductor. When the light hits the surface the charges flows away, and the LEDs are selectively switched off when an image pixel is required. It gets transported to the developer unit, a unit that contains toner particles. To simplify the complicated principle of the unit, it can be described that there is a charge and toner particles sticks to the charge. After passing the developer unit the belt is transported to a transfer nip. In the transfer nib, the fuse belt and the photoconductor belt are pressed firmly to each other using rollers. Usually the rollers have a steel core and a rubber layer. As the consequence, the toner transfers to the fuse belt. This is called contact transfer. The fuse belt (blue lines) is hot – about 100 degrees Celsius, and the toner becomes sticky (almost like chewing gum). The sticky toner is transported to the fuse nib. The paper is also fed to the fuse nib and two rollers press the toner firmly into the paper. This is called fusing, again done by contact transfer. The print is now ready and is transported to the paper finishers.

Figure 9.5: Details of the Contact transfer technology.

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The process modules in Figure 9.5 can print on one side of the sheet (simplex). To print both sides of the sheets, a turning station is used to reverse the paper. The schematic principle is drawn in Figure 9.6.

Figure 9.6: Turning station to reverse a page.

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The reversed paper is again transported to the process units and printed on the other side of the paper.

Figure 9.7: Turning station layout

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In Figure 9.7 the turning station is schematically drawn in the machine layout. Duplex technology using turning stations make controlling the paper flow more complex. Nevertheless, it is the only way to print two-sided prints using simplex print technology.

9.3. Duplex In the new system, Océ took the process units from the old machine, and mirrored it. Figure 9.8 schematically show the concept lay-out of the duplex engine.

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Figure 9.8: Mirrored Layout of the new system They also combined the fuse unit with the fuse rollers over above and fed the paper through the middle. In Figure 9.9 the schematic layout of the machine is shown. The mirror design can clearly be recognised, with similar photoconductor units and fuse units. The paper comes in at the left bottom of the machine following the red paper path. On its way it passes a registration unit. That unit can rotate and shift the paper, so that it aligns perfectly with the fuse nib. The paper is transported in the red paper path and leaves the machine on the right top.

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Figure 9.9: Duplex engine

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Figure 9.10 exhibits the engine when the doors are opened. The visible units in right and left are photoconductor belts. The fuse belts are not visible due to the heat insulation. At the bottom left, there is a drawer containing the registration unit.

Figure 9.10: Engine front view

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Figure 9.11: Paper path impression Figure 9.11 demonstrates an ‘artist impression’ of the paper path. The paper module is placed on the left – there is a stack of paper. Here you see the papers are following the paper path through the machine getting fed through the fuse all the way towards the stacker. There is no duplex loop or turning loop in the system. The advantage of the One-pass duplex design is its double image productivity while having only a single process speed. It also has a single paper speed so all the modules “around” it still only have to be designed for the low paper speed. And there is only a single set of peripherals like paper modules or a registration unit needed for double speed! The paper path in the system is straight instead of the traditional duplex loop. Registration also has the advantages of single edge measurement, meaning the system requires to measure the front edge only once (instead of twice for turning stations designs). Therefore the images are pressed simultaneously that results in an almost perfect front-to-back registration. Another advantage of the new system is that it avoids shrinkage of the paper after it heats up in the fuse nib. In conventional systems, the shrinkage could be up to 1 to 2%, so that should be taken into account when the second press on the back of the paper was taking place.

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There are some drawbacks to this design; one is inefficiency in case of one-sided documents when only half of the machine is used, hence the speed is half. The other is the complexity of the system, which is the consequence of combining two already complex systems. At the beginning of the developers were nervous about the estimated complexity. They estimated the number of unique parts of about 3,000, each needed to be engineered This complex set-up was only viable with a simple modular design; otherwise it was impossible to manage the development of this one-pass duplex machine.

9.4. Contact nibs

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One of the main issues Océ encountered with the duplex technology was related to the contact nibs. Figure 9.12 illustrates an example of the contact nibs including a roller with a steel core and a rubber layer on it driving the belt. In its yet-not-deformed state, the speed calculation of the belt is easy. However, since pressure is required for transfer the rollers are always in a deformed state. It may appear that speed would decreases in correspondence with the radius reduction. The actual situation is however different due to the rubber characteristics.

Figure 9.12: Contact nibs. The cross section of a roller on a surface can be seen in the Figure 9.13. In a rolling situation, the mass flow of the rubber layer is constant. There is no mass built up in a steady state. Since rubber is not compressible its mass density is constant.

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Figure 9.13: Contact nip creep

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These assumptions still apply in the middle of the contact where the thickness is reduced, so no compression of the rubber. However, the flow area of the rubber is reduced because of the deformation so the ‘flow’ speed has to increase! This effect is called rubber creep. For the speed calculations, the average speed of the rubber flow is needed. The formula commonly used in contact mechanics is: V ' 1  [ ˜ Z ˜ R

Figure 9.14: Contact transfer formula To calculate this formula for the foresaid situation advanced FEM systems are used. The ξ parameter is usually smaller than zero. Therefore, the speed in the deformed state is often faster than in normal one. According to the models the creep is a function of the net force, the rubber properties, the thickness of the layer, the radius of

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the roller, and much more. It can be regarded as a transmission ratio. To have a different transmission ratio the rubber properties or the net force can be altered. Downside is that the transmission ratio is also dependent on the tolerances of the net force and the rubber properties. Consequently the transmission ratio is rather a range than a fixed number.

9.5. Photoconductor belts

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The photoconductor belts are made from polyester strips, welded to a endless belt. The weld is non-printable because of mechanical and photoconductive properties. Figure 9.15 displays the right and left belt and the weld in red. In order to print an allocation algorithm is required to assign the images, in a way that the images are never located on the weld. The images on the left and right need to be synchronized because they are pressed simultaneously on the paper.

Figure 9.15: Non-printable weld Because of manufacturing tolerance on the belts and for instance thermal expansion due to the heat in the system both belts have a different length. In case of constant printing speed, when one photoconductor is larger than the other, the belt can drift into the image. This is an unacceptable error in a print. A solution to this problem is to synchronise the welds, so that the belt speed is an outcome according to the belt tolerance. A little offset in the speed of

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photoconductor is manageable for the developer unit and the print head.

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9.6. The speed control layout Synchronizing the welds of the belts means that the speed of the photoconductor can be different for the left and right process (Figure 9.16). According to the tolerances in the transfer nib, the transmission ratio also differs for the left and right; therefore, the speed of the fusebelt for the left and right process can be dissimilar. Both fuse belts make contact in the fuse nib. Too much of speed difference in the fuse belt can be problematic even though the rubber and the fuse belt can handle a limited amount of difference in speed. When the difference exceeds a certain amount, the fuse nib is likely to slip and the result is wear and damage. The damage results in shorter lifespan of the fuse belt. The resulting lifespan of the fusebelts in this system was found to be unacceptable. To overcome the problem developers increased the modelling effort over it. Several control concepts, drive positions, initialization concepts and adjustments have been tested. They attempted to use twin belts with the same tolerance and enlarge rollers to address the problem. They also conducted an extensive dynamic modelling of the stiffness of the belt, especially for the fuse belt. In spite of a thorough investigation carried out to grasp a better understanding of the system, they could not completely solve the problem. The principle problem of the system was the constrained design: all belt speeds were constrained, and the transmission ratios could not exactly be controlled because of manufacturing tolerances etc. A principal solution is trying to remove the over-constraints. If identical speeds could be assigned to both of the fuse belts no wear would occur in the fuse nib. With different transmission ratios in the transfer nib however the photoconductor speeds would differ and the welds would drift into the image. A breakthrough would be if Océ could develop a weld that allowed to be printed on. In that case the little difference in photoconductor belt speeds would not lead to any problems, and the big issue of lifespan of the fusebelt would be solved.

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Figure 9.16: Speed control layout

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The wear problem could be partly reduced at the cost of very complicated control systems. Having such complicated controls already at this stage of development indicated that the final machine would become too complex. For instance, a problem in the field would simply be too difficult to be solved by the service technicians.

Figure 9.17: Seamless belt speed control layout

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A ‘weld-less’ photoconductor showed to have some more benefits, that is depicted in Figure 9.18. This Figure shows the differences between the welded belt (on the left) and the seamless belt (on the right). In the welded set-up, the belts and the image allocation are optimised for the bulk sheets, but for large sheets there are combinations that do not fit well. So it has a productivity loss. Whereas, in the seamless belt system there is an optimal image allocation for all the sheets because they are simply printed after another. That means maximum productivity for any possible sheet length.

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Figure 9.18: Productivity fit Océ had to choose either for a mediocre certain solution based on complex control, or a good solution but with uncertain development which was a new welding process. Developing both solutions was not an option because of the limited resources so one should be chosen over the other. They eventually chose for the weld-less design because of its maximum productivity, simple design, and applicability to other printers, instead of putting all their efforts in a complicated machine-specific workaround. Figure 9.19 exhibits the cross-section of the new weld. The dark part in the picture is the cross-section having the thickness of about 130 microns. The grey area is the V-shaped laser weld. The challenge to

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this weld was not only developing a new welding process but also to get the right fatigue strength, because the weld turns throughout the machine and passes a large numbers of rollers and bends frequently.

Figure 9.19: Seamless OPC cross section.

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Topics for discussion and self-study 1. Make inventory of the main concepts and their coupling and interactions with the larger context outlined in this case study. Build up entirely your own visual transcript and transform it into an idea network. 2. What are the main relations and causalities that connect the items identified in question 1? How are they translated into processes and how effective are they? 3. Map the processes and challenges outlined in this case study onto two other case studies of your choice (also from this volume) and compare them. What conclusions do you draw? What advice can you give?

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Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved. doi:10.3233/978-1-61499-242-4-182

10. Need to know and obligation to share in NATO Intelligence, Surveillance and Reconnaissance (ISR) Coman C. (Christian)10 Senior Scientist, NATO, Netherlands, www.nato.int

Summary This case study of the Multi-sensor Aerospace-ground Joint Intelligence Surveillance and Reconnaissance (ISR) Interoperability Coalition (MAJIIC) project is an illustration of how large-scale system-level engineering design can be addressed in a multinational coalition. It is the objective of the engineering design process to align goals, stakeholders and technologies in an effective architecture. The key role of standardisation is illustrated in a distributed environment, and a spiral development process is adopted through different project phases in time.

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10.1. Background context Good afternoon, my name is Cristian Coman and I am with NATO Consultancy Command and Control Agency (NC3A), which is located in The Hague, The Netherlands. First of all, I would like to thank the organisers of this symposium, and in particular professor Spitas, for inviting me to contribute to this engineering design case study initiative. The cases presented this morning clearly outlined the design principles adopted in the development of specific systems or products. Throughout the morning session we learned that advanced engineering design is an unbounded domain. During my talk I would like to illustrate how these design principles applies to a large 10

Chapter transcribed and edited from Dr. Coman’s original CSiAED presentation

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capability composed of multiple systems. The presentation will focus on the design of a capability rather than the design of a system. In this context the capability is seen as a combination of systems, procedures and personnel. The title of the presentation is intricate, in particular when it comes to sharing of intelligence. Sharing of sensitive information, such as ISR data, has always been governed by a ‘need-to-know’ principle. Access to specific information was only granted if a good justification (a “need-to-know”) was presented. The need for a justification and the subsequent approval process prevented in some cases that critical information was delivered to a user in a timely manner. During recent operations NATO has learned that by adopting a more open attitude towards sharing information there is more to gain.. The MAJIIC project is a practical investigation of technologies, processes and people that can illustrate the benefits of timely sharing of information under an “obligation to share” principle. My talk will start with a short introduction, then I will discuss some aspects of the interoperability in NATO, which is at the core of the MAJIIC project. Furthermore I will present some achievements of the MAJIIC project and the way forward of this approach in NATO.

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10.2. Introduction to the MAJIIC project The MAJIIC project has been developed is the area of Intelligence, Surveillance and Reconnaissance (ISR). The meaning of the ISR terms within the NATO domain is presented in Figure 10.1 [AAP6]. Given the international character of the Alliance, NATO is very precise in standardizing the definitions of key terminology in order to ensure a common understanding across multiple nations. In other words, the intelligence is the discipline which is responsible for processing and exploiting sensor data in order to generate information. Surveillance is the systematic observation of an entity or a place by using sensors (for example a video camera). The reconnaissance represents the case when you want to gain more information about the activities and resources on a very specific area. Surveillance is systematic in nature whereas reconnaissance has a more exploratory character.

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Table 10.1: ISR explained Term Definition Intelligence “The product resulting from the processing of information concerning foreign nations, hostile or potentially hostile forces or elements, or areas of actual or potential operations.” Surveillance “The systematic observation of aerospace, surface or subsurface areas, places, persons, or things, by visual, aural, electronic, photographic, or other means.” Reconnaissance “A mission undertaken to obtain, by visual observation or other detection methods, information about the activities and resources of an enemy or potential enemy, or to secure data concerning the meteorological, hydrographic, or geographic characteristics of a particular area.” The ISR capabilities are commonly used in support to operations. The Command and Control (C2) processes govern the execution of military operations. The interconnection between the C2 processes and the ISR processes is depicted in Figure 10.1. In light-grey, on the right hand side in Figure 10.1 is the ISR loop which is also known as the Collection Coordination and Intelligence Requirements Management (CCIRM) process. The C2 process presented in darkgrey on the left hand side in Figure 10.1 includes the following steps: orient, decide, act and observe (also referred to as the ODAO loop). In a simplified view we have the military commanders managing the C2 processes and the ISR systems, such as radars and cameras are managed through the CCIRM processes. The goal of the ISR systems is to assure that the commander will have the right information at the right time to conduct the mission. What happens is that the commander has a continuous “need-to-know”. This is the standing state of the commander. He or she always wants to know what is happening with the enemy and with his or her own troops. However, the interaction of the C2 domain with the ISR domain is implemented through specific information requests. The information requests from the C2 loop flow into the CCIRM loop only on the basis of a need-toknow, which limits the utility of the information to the user that requested the information. The users do not have an overview of all existing information within the ISR domain. The MAJIIC project is addressing this inconvenience and introduces the idea that an

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“obligation to share” should exist in the ISR domain. All available information should be stored in a common repository such that everybody can have access to this information.

Figure 10.1: Operationalisation of ‘need to know’ and ‘obligation to share’ principles

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In addition, these are a few other lessons learned from NATO operations that triggered the initiation of this MAJIIC project. The most relevant are: a) lack of ISR assets, b) reduced interoperability, c) difficult access to data, d) not well defined processes. For example, there were Unmanned Aerial Vehicle (UAV) systems coming from country tried to send video information to troops from another country and this was not possible because the two countries were using different video encoding standards. Access to data is difficult and often data stays with the sensor systems and is a time consuming process to move the information from the data collector to the people who make decisions and people who would like to have the knowledge generated from this data and from this information.

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Moreover, many bodies, organizations and committees have been involved in numerous ISR efforts but despite significant efforts there has been little success in the overall coordination. Another coordination problem exists within the military organization and the way that the ISR assets are distributed across forces categories and how they are utilised. This problem is illustrated in Figure 10.2.

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Figure 10.2: The ISR coordination problem The coordination problem presented in Figure 10.2 can be presented from the interoperability perspective as well. Commonly, military categories such as air forces, navy, and army own ISR capabilities, Due to technical and/or operational interoperability limitations it is not possible to collectively use these assets. The benefit of using these assets commonly by all forces irrespective of the ownership can be approximated by the Metcalfe’s law, which states that the value of a communication network is proportional to the square of the number of users. A number of questions were addressed this morning in relation with the involvement of the user in the design process, and the scrum meeting appeared to be a popular approach. In MAJIIC the design process was from the beginning divided into three different areas: operational, architecture (or system) and technical. The user own owns the operation environment and the operational working group was created from the beginning. This ensured that the users are

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continuously involved into the project and not only periodically at decision points. The system level interoperability addresses the design of the architecture and the definition of business rules which are employed by the users to interact with the systems. The technical level interoperability supports the definition of data formats and standards that are used across systems.

Figure 10.3: An interoperability perspective on the design process: Coupling the system, technical and operational levels

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10.3. MAJIIC project architecture and development Everything started with an interoperability experiments conducted in Paris in 1997, when USA Joint STARS radar, which is an airborne radar, exchanged Ground Moving Target Indicator (GMTI) reports with a French helicopter, which also was equipped with the radar sensor. The Paris experiment revealed significant difficulties in exchanging radar information between the two systems in a timely manner (without human in the loop). Both systems collected information over the same geographic area but they were not able to exchange the information and complement if necessary. The initial experiment was extended into the Coalition Aerial Surveillance Reconnaissance (CAESR) project that lasted for about 4 years when the MAJIIC project continued the work. MAJIIC is a multinational project inside of NATO, and not all the NATO nations participate in this project. There are nine nations which decided to invest into the ISR interoperability domain and make sure that their assets where interoperable and they could exchange information and ISR sensor data in a seamless manner. About twenty-seven organisations and companies from the 9 MAJIIC nations are involved in this project.

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More than thirty-five command and control and ISR systems have been used over time in MAJIIC experimentations.

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Figure 10.4: Different ISR assets observing the area of operations The objectives of the MAJIIC project were mainly triggered by technological advances in the sensor and communication domains. It is common in current conflicts to have advance sensors deployed on mobile platforms that exchange information among them and with the end user over a network architecture. The operational concept assumed by MAJIIC is depicted at high level in Figure 10.4. The concepts include space borne systems, and airborne systems, which are flying at different altitude, and ground systems and maritime platforms as well.. Most of these platforms and systems are equipped with radars for detecting moving targets or collecting synthetic aperture radar (SAR) images, Systems that provides electronic support measurements are included in the MAJIIC concept of operation. Some of the platforms are equipped with electro-optical (EO) and infrared (IR) sensors. There is a wide variety of sensors which is used by those platforms. The operation concept also accounts for the fact that the sensors have different ranges of operations, from very short range of a few hundred meters up to long ranges in order of hundreds of kilometres. It was discovered in the beginning that the network interoperability can be easily achieved from a technical perspective. However this technical solution was not implemented independently of operational community. The overall goal of the project is to improve

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commander’s access to quality information. ISR capabilities should be concurrently developed from all three perspectives: operational, architectural and technical. MAJIIC proceeded in achieving the multilateral interoperability goal by identifying from the beginning that the key interface between systems will be at ground station terminal (GST) level. The working groups agreed that it is complicated to try achieving direct interoperability between all the moving assets. It was noted that it is easier to exchange data once this is available at the ground level in the control or exploitation station. In addition the possibility to disseminate data through existing or ad-hoc communication networks looked attractive. Common formats were recommended for exchanging ISR data over the network environment. Having this concept in place, it will facilitate the execution of the command and control function and at the same time exploit data or to transfer information between NATO domains and National domains. The central element to achieving the “obligation to share” goal was to develop a common repository for all information such that everybody was able to connect to the repository and publish and discover data.

Figure 10.5: MAJIIC architecture ([TN_986] and [TN_968]) Key to the MAJIIC engineering design process was to have permanent contact with the end user. The contact with the end user was maintained by challenging the operational working group to develop a concept of employment (CONEMP) that describes how the proposed technology will be used. Periodic exercises forced the user

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to think of developing Tactics, Techniques and Procedures (TTPs) to understand how they will use a common pool of capabilities. On the other side innovative technologies were continuously adopted during the development phases.

Figure 10.6: Technical interoperability scheme in MAJIIC MAJIIC quickly noted that the value of interoperability is null if the participants do not upload information into this system (Figure 10.6). Essential to this is to have people that are willing to share information and that the necessary agreements are in place.

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Table 10.2: Strategic decisions Permanent contact with the end user: a) Concept of employment (CONEMP) b) Tactics, techniques and Procedures (TTPs) Proven and innovative technologies: a) ISR architecture design principle b) Introduction of a Coalition Share Data (CSD) standard c) Move towards a Network Enable capability (Service Oriented Architecture) Figure 10.7 illustrates potential benefits of these interoperability progresses and how, in the MAJIIC concept, the assets will be used in a collaborative manner. Commonly, the wide area ground surveillance is executed with a radar installed on a flying platform 190

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though collecting data about entities moving on the ground. To give an impression about scale in this scenario, a wide area can extend about three hundred by three hundred kilometres and in this area there are dots which represent moving cars. With the radar flying at the altitude of ten thousand meters it is possible to observe continuously the cars moving within this large area. The GMTI radar information can be displayed on different maps. By changing the map backgrounds it is possible to highlight particular meanings of the overlaying information (see [TN_1080] for an overview of data used in MAJIIC).

Figure 10.7: Interoperability of different assets and exchange of information in real time on the operating theatre With GMTI radar sensors it is possible to collect broad information over a large area but not all detected targets in this area are of relevance to all users. To identify the relevant targets another system, such us an Electronic Counter Measure (ECM) system can be used to collects radio signals from targets. Once additional information is generated on some of the targets the commander may decide to acquire synthetic aperture radar images which suggest that in that area there is a runway and probably an airport as well. High191

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resolution synthetic aperture radar images can also be used along the runway to identify the airplanes in that area. The final identification can be conducted with an electro-optical camera when the air platform is in a position that provides visibility on the target. A scenario that involves multiple assets provided by different countries can be executed under the assumption that the participating systems are interoperable.

10.4. Spiral development

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The MAJIIC project adopted from the beginning a spiral development approach. This started in 2005 after the CAESAR project was completed. Each of the working group established under this project (operational, architecture and technical) was responsible for deriving specific requirements. Once the requirements were identified there was an implementation phase which was completed with a simulated exercise in 2006. During this exercise it was discovered that some of the things did not work correctly, and therefore new requirements were formulated. The next spiral arm started with the new requirements identified during previous exercise and was completed with another simulated exercise and a live exercise (called Trial Quest) in 2007, in Norway. About one thousand participants contributed to the Trial Quest exercise in 2007. The following spirals adopted the same approach with the last MAJIIC exercise being conducted in 2010. The design solution adopted in MAJIIC follows a spiral pattern (Figure 10.8). The requirements are validated and refined periodically during technical and live exercises. This approach allowed the user community to interact with the ISR systems during the development phases and subsequently permitted the users to provide sound observations regarding the functional aspects of technical systems (see Figure 10.9). Another spiral pattern was adopted in the refinement of the CONEMP. Many of the ISR systems developed within the MAJIIC framework support complex business processes. The introduction of information systems in the ISR domain has a direct impact on the way that the business processes are conducted.

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Figure 10.8: MAJIIC development process The key deliverable of the MAJIIC project is a series of technology baselines for supporting multinational operations in the area of ISR. The main technologies addressed within MAJIIC are related to: x Storage and dissemination of sensor data, management information and reports, x Exchange of near real time sensor data to include: video, imagery and radar. These baselines are expressed in terms of standardization agreements (STANAGs) and information technology architectures. When available, industry standards have been used in MAJIIC to achieve interoperability. However, given the particularity of the ISR domain, it has been necessary to also develop standards for improving interoperability in some particular areas. ISR related STANAGs are summarised in the overarching NATO ISR Interoperability Architecture (NIIA) [AEDP-2 2003], which includes standards for data representation, transmission, and exchange, as well as corresponding implementation guidelines. In MAJIIC, a subset of the STANAGs listed in NIIA has been actively exercised and maintained. This subset contains standards related to sensor data formatting and storage of data.

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Figure 10.9: Flow in the MAJIIC development process: Requirements validation and refinement

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10.5. Future planning After five years MAJIIC decided that it cannot only remain as a research and development project and the capabilities developed can be used in operations. Some of the systems have already been deployed to the operation. Challenges still exist since standard operating procedures (SOPs) needs to be developed for each specific theatre. Additional difficulties have been identified in the area of maintenance and operation support. Although the efforts at the end of the project concentrated on support to operations, the MAJIIC team would like to continue the development in this area. The new areas to be investigated are the integration of new sensor and data processing systems with the command and control systems and evolution towards service oriented architectures. MAJIIC has been constructed on server-client architecture and in the future the intention is to move towards service oriented architectures. MAJIIC would like to extend the set of sensor and information that can be shared and disseminated. Another direction of development is to move from a traditional military operation to a civil and military cooperation in an urban environment. The mobile computing is also a challenge for the future MAJIIC project. Thank you very much for your attention.

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Figure 10.10: Aspects of the next iteration of MAJIIC

Topics for discussion and self-study

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1. Make inventory of the main concepts and their coupling and interactions with the larger context outlined in this case study. Build up entirely your own visual transcript and transform it into an idea network. 2. What are the main relations and causalities that connect the items identified in question 1? How are they translated into processes and how effective are they? 3. Map the processes and challenges outlined in this case study onto two other case studies of your choice (also from this volume) and compare them. What conclusions do you draw? What advice can you give?

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Case Studies in Advanced Engineering Design C. Spitas, V. Spitas, M. Rajabalinejad (Eds.) IOS Press, 2013 © 2013 The authors and IOS Press. All rights reserved. doi:10.3233/978-1-61499-242-4-196

11. On engineering design methodology Spitas C. (Christos) Head of section Product Engineering, Faculty of Industrial Design Engineering, Delft University of Technology, Netherlands, www.tudelft.nl

Spitas V. (Vasilios) Faculty of Mechanical Engineering, National Technical University of Athens, Greece, www.ntua.gr

Summary In this article we introduce additional insights obtained during the symposium proceedings, which included a survey as well as workshops. Furthermore, we attempt a first study of the presented cases to identify common patterns, learn from them what aspects of the design methodology the industry places its attention on, and draw potentially useful conclusions about the nature of engineering design, as practiced today in the industry.

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11.1. Introduction From a theoretical standpoint, there is a large body of published work on the issue of design methodology, much of it dealing explicitly or implicitly with engineering design. From the workflows of Pahl and Beitz (1988) and VDI (1993), to the FMEA protocols of SAE (2009, 2013) and other engineering bodies, to six-sigma and other quality management schemes, to the various stage/ phase-gating schemes for project management that have proliferated since the 1940’s, many of the notions presented in these case studies –and used really by the industry– are not new. Contrast these also with the theories and models by Hubka (1987), Andreasen and Hein (1987), and Ehrlenspiel (1995) on integrated product development, Linde and Hill (1993) on contradiction-oriented innovation, Maimon and Braha (1999) on formal causal networks, Vajna (2005) on formal autogenetic design, Ottoson (2004) on dynamic product development, Gero (2004) on function-behaviour-structure networks, Hatchuel (2009) on concept-knowledge interaction, as well as the different 196

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approaches by Schön (1983) on ‘reflection in action’ and Cross (2008), just to name some of the important relevant academic research of the past few decades: When it comes to methods of working, caution and evolution seem to be the industry’s risk managed alternative to the scientists’ visions of revolutionary paradigm shifts (Eder, 1998). After all, Cooper (2011) warns that only one out of seven products entering development launches successfully- the risks facing the industry are clearly immense. And yet, we heard and read of things you will not find in standards: we heard and read of CERN building colossal Angstrom-accuracy cryogenically-cooled particle accelerators through a highly complex design, procurement and implementation procedure that constantly advances the state of the art; we read of ADAM challenging the much-acclaimed six-sigma model in its special context with a smart three-sigma model and ending up with a better process; of IRCTR combining and mastering multiple disciplines in order to advance our understanding of extreme weather, and improve the welfare of urban populations; of DSM restructuring the supply chain in favour and by virtue of a new accidentally discovered technology that in part reshaped its way of product design; of Océ-Canon at one time fighting to decouple -by design- phenomena that reduce the accuracy and performance of its printers, and at other times employing those same couplings to advantage, as technology and products co-evolve; and we read of NATO developing its highly complex systems interoperability in ways that best-in-class companies might envy, as per a spiral development model (Boehm, 1986). Not trivially, we read that we should deliver the product that a client really needs. We all know already that we are supposed to be doing this, but how often do we see this really done in our day? Here we shall refrain from reiterating or dissecting in depth this body of work, which we leave to the reader as a task, but instead we shall look afresh at the topic of engineering design by presenting the results of a survey we conducted during the symposium, and then taking a snapshot based on the case studies discussed in this book and summarising our own first findings, in an attempt to distil what ultimately it is that unites these so very different case studies: a set of fundamental patterns that are commonly present in manifestations of advanced engineering design.

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11.2. Results and discussion of a survey To fuel the present discussion, a questionnaire survey was conducted among the participants of the symposium on its first day, which is the day when the case studies were presented. The survey made use of the form in Appendix 1, adapted from Spitas (2011a), asking a total of 12 questions marked Q1-Q12.

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A total of 25 questionnaire replies were received and processed. Hereunder aggregate results for Q1-Q3 and Q5-Q8 are presented. Q9Q12 attracted less than 10 process-able replies and for reasons of statistical significance are not reported. The questions focused on the design process, as the respondents experience as well as envision it, and were preceded by three questions aiming to capture to some extent the demographics of the sample. The questions and answers are presented in the figures hereafter.

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Survey demographics: Q1-Q3

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Design process: Q5-Q8

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In terms of profiling the respondents, the influence of academic study in Q1 is reported to be 37%. Influence of on-the-job-training (OJT) is 201

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reported to be 31% and of seminars 8%. Influence of own initiative is reported on average to be 20%, whereas other influences are credited on average with 3%. Drawing any definitive conclusion should be risky, but it can be offered as an observation that academic study over time does not account for the largest impact, versus all other influences combined, as other sources of knowledge become available to engineers (OJT, seminars, own initiative). Q2-Q3 afford a simple glance at the demographics behind these answers.

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Q5 reveals an interesting aggregate view on the effect of the designer’s experience on the designer’s systematicism, where ‘more experienced tend to be more systematic’ was credited on average with 61% and ‘more experienced tend to be less systematic’ was credited on average with 30%. In both cases the standard deviation was quite high at just under 50%. ‘More experienced tend to be no less systematic’ was credited on average with 9%, with a standard deviation of 30%. The high standard deviations negate the possibility of drawing conclusions other than to confirm that this question clearly concerns a highly debatable topic. Q6 shows a predominance of the ‘abstraction to detail’ design paradigm with an average occurrence degree/ relative frequency of 62%, followed by ‘detail to detail directly’ with 19%, ‘detail to abstraction to detail’ with 11%, and ‘other paradigm’ with 8%. Standard deviations for these statistics range from 16% to 32%. In spite of the large uncertainties involved, the present results seem to strengthen the impression that ‘abstraction to detail’ is a dominant paradigm of design and that ‘detail to detail’ has a consistent if by comparison minor role in the overall design process. Again, however, the large standard deviations do not allow safe conclusions. To the general question ‘To what degree (0-100%) would you say that the existing design process in your company/ organisation is efficient?’ the replies gave an average of 50% with a standard deviation of 25%. Q7 offers a somewhat different picture than Q6, in that ‘detail to abstraction to detail’ is more preferred with an average occurrence degree/ relative frequency of 22% (versus 11% in Q6), whereas ‘detail to detail directly’ is somewhat less preferred on average with 14% (versus 19% in Q6) and ‘abstraction to detail’ still being the dominant paradigm with 57% (versus 62% in Q6). Standard deviations for these statistics range from 16% to 25%.

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Interestingly, to the question ‘What efficiency do you believe that your company/ organisation could achieve in its design process?’ the replies gave an average of 68% with a standard deviation of 24%, which shows an increase of 18% compared to the current process depicted in Q6. While the standard deviations of the statistics are too large to allow conclusions to be drawn with any safety, if we suppose a cause-and-effect relationship between the paradigm employed and the efficiency of the design process, then it can be postulated that the relative increase in the degree/ frequency of employment of the ‘detail to abstraction to detail’ paradigm is expected by the respondents to yield an increase in design efficiency.

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Finally, Q8 sheds some light to the decision-making process, and in particular to how the decision is made to stop looking for alternatives and start elaborating the best one. Best judgement is reported to be used with an average frequency of 39%, reaching consensus with a frequency of 21%, the passing of adequate time searching with 20%, the finding of an adequate number of alternatives with 14%, while not looking for alternatives is also practiced with a frequency of 6%. There is no reported use of convergence metrics. The standard deviation ranged from 13% to 34%. The foremost result of this survey has to be the large deviation of opinions and practices within the (small) survey sample itself. Of course, this study cannot claim to be anything more than a snapshot of the participating population of one specific symposium. This snapshot suggests the following: x Academic study is an important influence but becomes less so with accumulating experience, OJT, self-study, seminars and other training opportunities. x It is highly debatable whether and in what manner accumulating experience has an effect on a designer’s systematicism. It is possible that there is no simple correlation. x An increased degree/ relative frequency of using a ‘detail to abstraction to detail’ design paradigm may be related to an increased efficiency of the engineering design process.

11.3. Discussion of the case studies The same variety can be seen in the engineering design approaches featured in the case studies. The degrees of abstraction differ, as do

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the apparent points of focus. Driving considerations vary. Stakeholder structures, missions, team sizes and organisation vary. Terminology varies. They all share, however, patterns that become quite visible when reviewed and contrasted closely. Some main observations are as follows:

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The workflow in advanced engineering design does not seem to globally adhere to any singly defined mode, at least in algorithmic terms. It is manifestly a causally-driven (need-driven), goal-oriented, analysis-supported systematic process of risk-managed choices through several levels of idea abstraction, fuelled by the present awareness of the knowledge space (spanning from abstraction to specification), and in effect exploring it further and adding to said awareness. Engineering design is clearly a mixed product of knowledge, experience, motivation, method and intensive work. It scans the design space, eventually in a spiral manner, increasing knowledge and understanding with each iteration. Figure 11.1 explains this process in a formally defined directionally organised ‘space of ideas’ (Spitas, 2011b), where project flow can alternate between the two directions and combine these (notice branches starting from abstract wishes, specific ideas or existing products, and anywhere in between where existing knowledge can provide such starting point. Furthermore, each idea visited adds to the knowledge, and thus provides new possible starting points for future development. This makes a spiral development process meaningful and potentially advantageous (i.e. ref. Cases 6, 10 etc). Taking inventory from the case studies, we can consider as manifestations of advanced engineering design actions such as to: a) Identify the user needs correctly and in depth (i.e. ref. Case 2) b) Identify the interrelations of the design requirements with existing design-space practices and rules (i.e. ref. Cases 5,9) c) Identify dead-ends in the process, validate, quantify risks and come up with contingency plans (i.e. ref. Case 6, 9) d) Try to visit the concept-space (abstracted) and the productspace (specific) for fresh thoughts e) but know when to stop: advanced engineering design is results-oriented (i.e. ref. Case 3) f) Look at problems with a fresh attitude and dare to challenge the known art and/ or best practices (i.e. ref. Case 1, 4, 5, 9), including the value-and-supply-chain organisation (i.e. ref. Case 7).

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Based on the same case studies, we can consider engineering design to be managed effectively inasmuch as: g) A funnel-like tollgate-controlled process from abstraction to specification is observed (i.e. ref. Cases 3, 7, 10) h) Risks are recognised and well accounted for (i.e. ref. Cases 1, 6) i) Team awareness and targeted communication promote both individual thinking and coordination (i.e. ref. Case 2) j) Multidisciplinary approach to the same problem is encouraged (ref. all cases) k) Reuse of knowledge and leveraging of external knowledge, through co-development, collaborations or licensing, is used as much as possible (ref. Case 2, 7) If we define the core process of engineering design as comprising the above points, we can see that this process is more or less discernible in –and thus unifies- all case studies; however it gives at a macromethodological scale context-sensitive manifestations: Depending on the social, business and technological context, this workflow may manifest itself in different ways, i.e. as a predominantly synthetic journey from abstraction to specification, or as a mixed syntheticanalytic journey from specification to abstraction to specification. Most case studies show explicitly a frequent alternation and interaction between tangible realities and new concepts. These must be as much as possible synchronised throughout the development process (i.e. ref. Case 2), which can iterate over the same ‘ground’, or part of the space of ideas (Spitas, 2011b), through subsequent development projects in a spiral manner (i.e. ref. Cases 6, 10), or iterations within the same project. This concept is depicted more formally in Figure 11.1. The analytic (specification to abstraction) branch of this process, in the context of advanced engineering, when of a significant magnitude, is scientific research, which is in many cases intertwined with product development, sometimes leading (and creating awareness of new needs and opportunities, i.e. ref. Case 7) and other times following (and creating solutions, i.e. ref. Case 8).

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Figure 11.1: Depiction of a systematic engineering design process as a journey populating the space of ideas/ knowledge (here shown in the form of a knowledge density function: grey areas). The population of the space of ideas with new knowledge is seen as an increase in the idea density.

Bibliography 1. Andreasen M.M., Hein L. (1987), Integrated product development, Springer-Verlag 2. Braha D., Maimon O. (1999), A mathematical theory of design: modeling the design process (Part II), International Journal of General Systems, 27 (4), 319–347 3. Boehm B. (1986), A Spiral Model of Software Development and Enhancement, ACM SIGSOFT Software Engineering Notes, ACM, 11(4), 14-24

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4. Cooper R. (2011), Winning at New Products: Creating value through innovation, Basic Books 5. Cross N. (2008), Engineering design methods: strategies for product design, 4th ed., John Wiley & Sons 6. Eder E. (1998), Design Modelling-A Design Science Approach (and Why Does Industry Not Use It?), Journal of Engineering Design, 9(4), 355-371 7. Ehrlenspiel K. (1995), Integrierte Produktentwicklung, Carl Hanser Verlag 8. Gero J.S., Kannengiesser U. (2004), The situated function– behaviour–structure framework, Design Studies, 25, 373–391 9. Hatchuel A., Weil B. (2009), C-K design theory: An advanced formulation, Research in Engineering Design, 19(4), 181–192 10. Hubka V. (1987), Principles of Engineering Design, Butterworth Scientific 11. Linde H., Hill B. (1993), Erfolgreich erfindenWiderspruchsorientierte Innovationsstrategie für Entwickler und Konstrukteure, Hoppenstedt Technik und TabellenVerlag 12. Maimon O., Braha D. (1999), A mathematical theory of design: representation of design artifacts (Part I), International Journal of General Systems, 27 (4), 275–318 13. Ottosson S. (2004), Dynamic product development – DPD, Technovation: The International Journal of Technological Innovation and Entrepreneurship, 24 (11), 179–186 14. Pahl G., Beitz W. (1988), Engineering design: A systematic approach, The Design Council 15. SAE International (1999), Potential Failure Mode and Effects Analysis in Design (Design FMEA), Potential Failure Mode and Effects Analysis in Manufacturing and Assembly Processes (Process FMEA), Standard J1739 16. SAE International (2013), Design Review Based on Failure Modes (DRBFM), Standard J2886 17. Spitas C. (2011a), Analysis of systematic engineering design paradigms in industrial practice: A survey, Journal of Engineering Design, 22(6), 427-445 18. Spitas C. (2011b), Analysis of systematic engineering design paradigms in industrial practice: Scaled experiments, Journal of Engineering Design, 22(7), 447-465 19. Schön D.A. (1983), The reflective practitioner, Harper Collins

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20. Vajna S., Clement S., Jordan A. (2005), The autogenetic design theory: an evolutionary view of the design process, Journal of Engineering Design, 16 (4), 423–440 21. VDI (1993), Richtlinie VDI2221: Methodik zum Entwickeln und Konstruieren technischer Systeme und Produkte, VDIVerlag

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Editorial summary of main conclusions The workflow in advanced engineering design does not globally adhere to any single methodology. It is a causally-driven (needdriven), goal-oriented, analysis-supported

systematic process

choices through several levels of idea abstraction, fuelled by the present awareness of the knowledge space (spanning from abstraction to specification), and in effect exploring it further and adding to said awareness. Advanced of risk-managed

engineering design is a mixed product of knowledge, experience, motivation, method and hard work. It scans the design space,

spiral manner

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eventually in a , increasing knowledge and understanding with each iteration. It entails the following: a) Identify the user needs correctly and in depth, b) Identify the interrelations of the design requirements with existing design-space practices and rules, c) Identify dead-ends in the process, validate, quantify risks and come up with contingency plans, d) Try to visit the concept-space (abstracted) and the product-space (specific) for fresh thoughts, e) but know when to stop: advanced engineering design is results-oriented. It can be managed as long as f) The funnel-like tollgate-controlled process from abstraction to detail is observed, g) Risks are recognised and well accounted for, h) Team awareness and targeted communication promote individual thinking, i) Multidisciplinary approach to the same problem is encouraged. The core process is identical, however it gives at a macro-

context-sensitive

methodological scale manifestations: I.e., depending on the social, business and technological context, this workflow may manifest itself in different ways, i.e. as a predominantly synthetic journey from abstraction to specification, or as a mixed synthetic-analytic journey from specification

to

abstraction to specification. The analytic (specification to abstraction) branch of this process, in the context of advanced engineering, when of a significant magnitude, is scientific research.

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Appendix 1

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Survey questionnaire form

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Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

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Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

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Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

Appendix 2 Workshop topics Topic 1: Knowledge-based decision making in Advanced Engineering Design Sub-topics 1. Individual designers and company structure/procedures play vital roles in developing AED. Quantify and explain the contribution of each. (Excellent designers in mediocre environment vs. the opposite) 2. Method with low experience vs. high experience with little method 3. When to stop. Examples 4. Current level, goal, examples Topic 2: On the how of transformations: from academic knowledge to industrial practice and from student to competent engineer

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Sub-topics 1. How is it done? Identify critical points in the process. The role of training from university to company. 2. Which skill set is acquired in each step? (current and proposed) 3. Deep mathematical background vs. wide technological knowledge. 4. Group work vs. individual work (quantify)

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Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

Appendix 3 Synaptic networks and associated notation A complete description of idea class elements, synaptic networks, their associated notation and graphical representation is given in Spitas (2011, 2012, 2013). Here the main elements are summarised to offer a working method of representing, analysing and validating ideas and their relationships, as reported in the case studies.

Modelling of ideas: Fundamental considerations

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We postulate that the ‘idea’, stripped from any other connotation than its lexicographical meaning, is central to describing everything in the context of human cognitive activity, including design. To a human, an idea is anything that is actually or potentially present to consciousness (Merriam-Webster, 2012). This is also backwardcompatible to existing theories, as those reviewed in Chapter 11. Further, ‘idea’ is casually used in the context of the more abstracted levels of product development and in fact any innovative thought, envisioned embodiment of an artefact or process, foresight, etc. is commonly referred to as an idea: ‘I have an idea!’ (Spitas, 2011). There are those who would assign the words ‘idea’, ‘concept’ (also: ‘knowledge’) and ‘embodiment’ to ideas of increasing level of maturity (or detailing) within the design process, but if we consider the natural semantics of the words (Merriam-Webster, 2012) this is an artificial restriction: i.e. there is no reason, given the lexicographical definition of ‘idea’, why ‘concept’ should mean anything different. The all-encompassing definition of ‘idea’ admittedly poses challenges to the computer implementation, but has an obvious benefit to offset this challenge: because it is the common denominator of all the more specialised representations of cognitive objects, it allows the cross-talk of domains that use very different representations, terminology, and relationships. In fact, ideas suffice to represent ‘things’, relations between ‘things’, and so forth, across any conceivable level of abstraction and allows to cross any preconceived barriers between ontology and function: i.e. Define ‘red’: is it a colour, an object property, or a descriptor of a function, subject to lighting conditions and the state of the human eye receptor? Or: When a ‘concept’ becomes ‘knowledge’, does it stop being a concept, as in ‘present to consciousness’ (Merriam-Webster, 2012)? 215

Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.

Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

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Such paradoxes found in orthodox Frame-based classifications are no longer relevant when we adopt the idea-class as the single root class in the cognitive domain. Additionally, engineering design entails the consideration, representation and manipulation of ideas not only referring to the product system itself, but also at least the user(s), the business/ enterprise(s) developing and otherwise related to the product, and further the context at large, society and the environment. These ideas belong to very different domains, but are obviously and essentially coupled, as shown in Figure A3.1. In such a situation it becomes vital to use such a common denominator as is the ‘idea’, if only to assure that indeed such cross-talk can take place.

Figure A3.1: Systems view of engineering design (in circle) and couplings to the essential context; ideas pertain to very different domains

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Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

Graphical representation Here we provide a set of primitives and examples for graphically representing ideas using two alternative representations: a formal (explicitly showing attributions as directional curves/ arrows) and a simplified one, where ideas can be represented also as curves (crossing their attributes). Ideas attributed to other ideas can be understood as properties, functional arguments etc On the right side of Figure A3.2 we offer a comprehensive representation of a law of mechanics in the form of a network. We term such a network ‘synaptic network’ after ‘synapsis’: a link/ operator between two ideas that is itself an idea. Ideas can be assigned values and truth states, which can be indicated next to ideas in these representations as needed (not shown here). This example also illustrates mixed use of formal and simplified representations to improve readability.

Figure A3.2: Primitives and examples for the graphical representation of ideas, featuring combinations of formal and simplified notation

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The primitives shown in Figure A3.2 are normally sufficient for representing all ideas.

Operations: Formal use of synaptic networks Synaptic networks afford the possibility to implement knowledge as abstract as laws (i.e. physical laws), and then have models automatically emerge from these. In the present paradigm we consider that rules and in general operations are ideas also and share therefore all the definitions and properties given in the previous sections. Operations evaluate dynamically, based on ideas passed as arguments. Examples are

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Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

shown in Table A3.1. If such operations are defined, then values or truth states of ideas may be checked systematically for consistency. Table A3.1: Idea operator implementations

(a) Generic operation, class independent

(b) Rule implementation using ‘floating’ attributions

The absence of class-restrictions means that operators can be made generic and later specified ad-hoc as needed. Obviously, operations will not evaluate until the ideas operated on are made compatible to such evaluation (i.e. are specified enough), but it is important that in the meantime the operation can act as a meaningful placeholder, prompting what is still needed before it can evaluate. Additionally, the generic nature of many laws can best be captured in a type-neutral way, as i.e. in Table A3.1-b, which shows the relationship between displacement, force and work: Laws can be represented as rules bundled with ‘floating’ attributions external to the idea definitions (as opposed to operations being embedded into classes themselves, as per the object oriented paradigm). Using Lisplike pseudo-code we can represent this as:

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(operation (x f w) ((= (* x f) w) (attr-q x displacement) (attr-q f force) (attr-q w work)))

where attr-q returns ‘true’ if the first argument is an attribute of the second argument, in our case if x is attributed to the set of displacements etc This conveys the law that work is equal to the product of displacement and force. It can readily be generalised to all kinds of Lagrangian and Hamiltonian DOFs by abstracting displacement and force accordingly. As a second example, consider the following representation of the equilibrium of a body:

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Spitas C., Spitas V., Rajabalinejad M. (Eds.) Case Studies in Advanced Engineering Design

(operation (body) (= (+ (all x (and (attr-q x body) (attr-q x force)))) 0))

where all returns a list of all ideas x for which the second argument is true.

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Establishing and validating relationships and causalities Synaptic networks may be used to understand and visualise relationships and causalities between ideas. I.e. often an engineer may believe intuitively that two ideas are related, but this intuitive level of perception does not allow to distinguish clearly between causality, mere correlation, or even more trivial coincidence. Therefore intuitive decisions can be wrong, when correlation or coincidence are confused with causality. Synaptic networks can be used beneficially in two ways in this context: 1. To assess the relevance of ideas and the strength or weakness of such relationships: Strongly related ideas are situated ‘close-by’ in a synaptic network, hence within distance of one or two synapses. They may often bear strong correlations in their values or truth states. Ideas farther apart in a synaptic network are more likely to be weakly related. This assessment serves to root out false intuitive impressions, such as arising from i.e. coincidence or false beliefs. 2. To establish causality between ideas in a synaptic network, not only relevance should be established as per point 1, but one should appear explicitly as an attribute to the other(s). Furthermore in the course of good practice the degree of (in)sensitivity to the context should be established by varying the latter and re-testing.

Bibliography 1. Merriam-Webster Online Dictionary and Thesaurus (2012), http://www.merriam-webster.com/ 2. Spitas C. (2011b), Analysis of systematic engineering design paradigms in industrial practice: Scaled experiments, Journal of Engineering Design, 22(7), 447-465

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3. Spitas C. (2012), Definition of a functional class of ideas for Integrated Product Development and supporting theory, 9th International Workshop on Integrated Product Development, 5-7 Sept 2012, Magdeburg 4. Spitas C. (2013), Beyond frames: A formal humancompatible representation of ideas in design using non-genetic ad-hoc and volatile class memberships and corresponding architecture for idea operators, International Conference on Engineering Design 2013 (ICED13), 19-22 August 2013, Seoul, Korea

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Case Studies in Advanced Engineering Design : Proceedings of the 1st International Symposium, edited by C. Spitas, et al., IOS Press, Incorporated, 2013.