Joining and assembly of medical materials and devices

574 Pages·2013·35.537 MB·English

by  Y (Norman) Zhou, Mark D. Breyen

Joining and assembly of medical
materials and devices

© Woodhead Publishing Limited, 2013
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© Woodhead Publishing Limited, 2013
Woodhead Publishing Series in Biomaterials: Number 54
Joining and assembly
of medical materials
and devices
Edited by
Y. (Norman) Zhou and
Mark D. Breyen

Oxford Cambridge Philadelphia New Delhi
© Woodhead Publishing Limited, 2013
Published by Woodhead Publishing Limited,
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First published 2013, Woodhead Publishing Limited
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ISBN 978-1-84569-577-4 (print)
ISBN 978-0-85709-642-5 (online)
ISSN 2049-9485 Woodhead Publishing Series in Biomaterials (print)
ISSN 2049-9493 Woodhead Publishing Series in Biomaterials (online)
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© Woodhead Publishing Limited, 2013
Contents
Contributor contact details x iii
Woodhead Publishing Series in Biomaterials x vii
Part I Fundamentals of joining and assembly in
medical materials and devices 1
1 Introduction to medical materials and devices 3
J. J. Ramsden, Collegium Basilea, Switzerland
1.1 Introduction 3
1.2 The anatomy of interaction 1 0
1.3 Materials for drug delivery 2 0
1.4 The metrology of biocompatibility 2 1
1.5 Conclusion 23
1.6 Future trends 24
1.7 Sources of further information 2 4
1.8 References 24
2 Introduction to joining methods in medical
applications 28
L. Quintino, Technical University of Lisbon, Portugal
2.1 Introduction 28
2.2 Welding processes 33
2.3 Adhesive bonding 41
2.4 Examples of applications 4 3
2.5 References 45
v
© Woodhead Publishing Limited, 2013
vi Contents
3 Microwelding methods in medical components
and devices 4 7
K. J. Ely, GlaxoSmithKline Corporation, USA, P. Hall,
Boston Scientic Corporation, USA and Y. Zhou, University
of Waterloo, Canada
3.1 Introduction 4 7
3.2 Materials challenges 4 9
3.3 Medical components and devices 5 6
3.4 Joint design and process selection 6 5
3.5 Testing and verifi cation 7 3
3.6 Conclusion and future trends 7 6
3.7 References 7 7
4 The effects of sterilization on medical materials and
welded devices 7 9
W. J. Rogers, Consultant, USA
4.1 Introduction to sterilization 7 9
4.2 Sterilization methods 8 0
4.3 The effects of sterilizing on different materials 9 6
4.4 The effects of sterilizing on welded joints 1 21
4.5 Selecting a suitable sterilization method 1 26
4.6 Conclusions 127
4.7 Sources of further information 1 28
4.8 References 129
Part II Joining and assembly of medical metals 131
5 Micro-welding of shape-memory alloys 133
M. I. Khan, Smarter Alloys, Canada and Y. Zhou,
University of Waterloo, Canada
5.1 Introduction 133
5.2 Fundamentals of Nitinol shape-memory alloys 134
5.3 Micro-welding of NiTi 1 38
5.4 Future trends 151
5.5 Conclusion 152
5.6 References 152
© Woodhead Publishing Limited, 2013
Contents vii
6 Joining of platinum (Pt) alloy wires to stainless steel
wires for electronic medical devices 1 54
A. Pequegnat and Y. Zhou, University of Waterloo, Canada
6.1 Introduction 154
6.2 Material properties 155
6.3 Material challenges in joining 156
6.4 The crossed-wire joint 1 59
6.5 Joining processes 162
6.6 Future trends 1 74
6.7 Conclusions 1 74
6.8 References 175
7 Evaluating the corrosion performance of metal
medical device welds 178
S. C. Kelley and D. F. Untereker, Medtronic, Inc., USA
7.1 Introduction 178
7.2 Measurements of corrosion 1 83
7.3 Direct measurements of corrosion current 1 88
7.4 Considerations when gathering corrosion data 1 96
7.5 Test sample preparation 198
7.6 Instrumentation and equipment 2 01
7.7 Interpretation of data 2 04
7.8 Mitigations for weld corrosion 2 05
7.9 Future trends 206
7.10 Sources of further information 2 07
7.11 References 207
8 Laser hermetic welding of implantable medical
devices 211
J. Xie, Advanced Bionics, USA
8.1 Introduction 211
8.2 Hermetic-sealing techniques 2 12
8.3 Laser conduction welding 214
8.4 Focused laser beams 222
8.5 Laser welding parameters 225
8.6 Requirements for laser hermetic welds 2 28
8.7 Conclusion and future trends 2 33
8.8 References 235
© Woodhead Publishing Limited, 2013
viii Contents
9 Validating hermeticity in welded metallic implantable
medical devices 2 36
K. J. Ely, GlaxoSmithKline Corporation, USA
9.1 Introduction 236
9.2 The physics of leak rates 237
9.3 Measurement of leak rates – testing and verifi cation 249
9.4 Determining leak rate based on helium content 2 52
9.5 References 257
Part III Joining and assembly of medical plastics 2 59
10 Overview of welding methods for medical plastics 261
H. J. Yeh, Amgen Inc., USA
10.1 Introduction 261
10.2 Fundamental processes of plastics welding 2 63
10.3 Medical plastics and weldability 2 67
10.4 Part and joint design 269
10.5 Processes with external heating 2 71
10.6 Processes with internal heating 2 79
10.7 Processes with implant welding 2 83
10.8 Potential impacts from other manufacturing processes 2 86
10.9 Special applications for welding of medical plastics 2 87
10.10 References 295
11 Ultrasonic welding of medical plastics 2 96
H. J. Yeh, Amgen Inc., USA
11.1 Introduction 296
11.2 Ultrasonic-welding processes fundamentals 2 97
11.3 Ultrasonic-welding process parameters and control 3 02
11.4 Weldability 306
11.5 Horn design 309
11.6 Part and joint design 313
11.7 Process optimization 3 17
11.8 Other specifi c applications 3 18
11.9 Troubleshooting 320
11.10 Advantages and limitations 3 21
11.11 References 322
© Woodhead Publishing Limited, 2013
Contents ix
12 Radio frequency (RF)/dielectric welding of
medical plastics 323
H. J. Yeh, Amgen Inc., USA
12.1 Introduction 323
12.2 Dielectric heating fundamentals 3 24
12.3 Dielectric welding/sealing process description and process
parameters 3 27
12.4 Key factors affecting the sealing process and seal quality 3 33
12.5 Weldability 338
12.6 Testing approaches for seals and the dielectric sealing process 3 38
12.7 RF welding process advantages, limitations and future trends 3 41
12.8 Reference 343
13 Transmission laser welding strategies for
medical plastics 344
I. Jones, TWI Ltd, UK
13.1 Introduction 344
13.2 Advantages and limitations of laser welding 3 44
13.3 Process description 3 45
13.4 Main welding parameters and effects 3 49
13.5 Forms of equipment 350
13.6 Weldable materials 356
13.7 Joint designs 359
13.8 Monitoring and quality control 3 60
13.9 Applications 360
13.10 References 368
14 Bonding strategies and adhesives for joining medical
device components 370
K. Chaffin, C. Taylor and T. Grailer, Medtronic, Inc., USA
14.1 Introduction 370
14.2 Designing a joint with adhesive 371
14.3 Mechanisms of adhesion 388
14.4 Adhesion promotion 395
14.5 Types of adhesives used in medical devices 3 97
14.6 Conclusion 401
14.7 Sources of further information and advice 4 02
14.8 References 402
© Woodhead Publishing Limited, 2013