Whilst inkjet technology is well-established on home and small office desktops and is now having increasing impact in commercial printing, it can also be used to deposit materials other than ink as individual droplets at a microscopic scale. This allows metals, ceramics, polymers and biological materials (including living cells) to be patterned on to substrates under precise digital control. This approach offers huge potential advantages for manufacturing, since inkjet methods can be used to generate structures and functions which cannot be attained in other ways.
Beginning with an overview of the fundamentals, this bookcovers the key components, for example piezoelectric print-heads and fluids for inkjet printing, and the processes involved. It goes on to describe specific applications, e.g. MEMS, printed circuits, active and passive electronics, biopolymers and living cells, and additive manufacturing. Detailed case studies are included on flat-panel OLED displays, RFID (radio-frequency identification) manufacturing and tissue engineering, while a comprehensive examination of the current technologies and future directions of inkjet technology completes the coverage.
With contributions from both academic researchers and leading names in the industry, Inkjet Technology for Digital Fabrication is a comprehensive resource for technical development engineers, researchers and students in inkjet technology and system development, and will also appeal to researchers in chemistry, physics, engineering, materials science and electronics.
Table of Contents:
About the Editors xiii
List of Contributors xv
Preface xvii
1. Introduction to Inkjet Printing for Manufacturing 1
Ian M. Hutchings and Graham D. Martin
1.1 Introduction 1
1.2 Materials and Their Deposition by Inkjet Printing 3
1.2.1 General Remarks 3
1.2.2 Deposition of Metals 3
1.2.3 Deposition of Ceramics 6
1.2.4 Deposition of Polymers 7
1.3 Applications to Manufacturing 8
1.3.1 Direct Deposition 9
1.3.2 Inkjet Mask Printing 12
1.3.3 Inkjet Etching 13
1.3.4 Inverse Inkjet Printing 14
1.3.5 Printing onto a Powder Bed 15
1.4 Potential and Limitations 15
References 17
2. Fundamentals of Inkjet Technology 21
Graham D. Martin and Ian M. Hutchings
2.1 Introduction 21
2.2 Surface Tension and Viscosity 23
2.3 Dimensionless Groups in Inkjet Printing 25
2.4 Methods of Drop Generation 27
2.4.1 Continuous Inkjet (CIJ) 27
2.4.2 Drop-on-Demand (DOD) 28
2.4.3 Electrospray 33
2.5 Resolution and Print Quality 34
2.6 Grey-Scale Printing 35
2.7 Reliability 36
2.8 Satellite Drops 38
2.9 Print-Head and Substrate Motion 39
2.10 Inkjet Complexity 42
References 42
3. Dynamics of Piezoelectric Print-Heads 45
J. Frits Dijksman and Anke Pierik
3.1 Introduction 45
3.2 Basic Designs of Piezo-Driven Print-Heads 47
3.3 Basic Dynamics of a Piezo-Driven Inkjet Print-Head (Single-Degree-of-Freedom Analysis) 49
3.4 Design Considerations for Droplet Emission from Piezo-Driven Print-Heads 60
3.4.1 Droplet Formation 60
3.4.2 Damping 66
3.4.3 Refilling 67
3.4.4 Deceleration Due to Elongational Effects Prior to Pinching Off 70
3.4.5 Summary 71
3.5 Multi-Cavity Helmholtz Resonator Theory 71
3.6 Long Duct Theory 77
3.7 Concluding Remarks 83
References 84
4. Fluids for Inkjet Printing 87
Stephen G. Yeates, Desheng Xu, Marie-Beatrice Madec, Dolores Caras-Quintero, Khalid A. Alamry, Andromachi Malandraki and Veronica Sanchez-Romaguera
4.1 Introduction 87
4.2 Print-Head Considerations 88
4.2.1 Continuous Inkjet (CIJ) 88
4.2.2 Thermal Inkjet (TIJ) 88
4.2.3 Piezoelectric Drop-on-Demand (Piezo-DOD) 89
4.3 Physical Considerations in DOD Droplet Formation 89
4.4 Ink Design Considerations 95
4.5 Ink Classification 95
4.5.1 Aqueous Ink Technology 96
4.5.2 Non-aqueous Ink Technologies 100
4.6 Applications in Electronic Devices 105
4.6.1 Organic Conducting Polymers 105
4.6.2 Conjugated Organic Semiconductors 106
4.6.3 Inorganic Particles 107
References 108
5. When the Drop Hits the Substrate 113
Jonathan Stringer and Brian Derby
5.1 Introduction 113
5.2 Stable Droplet Deposition 114
5.2.1 Deposition Maps 114
5.2.2 Impact of Millimetre-Size Droplets 116
5.2.3 Impact of Inkjet-Sized Droplets 119
5.3 Unstable Droplet Deposition 120
5.4 Capillarity-Driven Spreading 122
5.4.1 Droplet–Substrate Equilibrium 122
5.4.2 Capillarity-Driven Contact Line Motion 124
5.4.3 Contact Angle Hysteresis 125
5.5 Coalescence 126
5.5.1 Stages of Coalescence 126
5.5.2 Coalescence and Pattern Formation 128
5.5.3 Stable Bead Formation 128
5.5.4 Unstable Bead Formation 130
5.6 Phase Change 131
5.6.1 Solidification 132
5.6.2 Evaporation 132
5.7 Summary 134
References 135
6. Manufacturing of Micro-Electro-Mechanical Systems (MEMS) 141
David B. Wallace
6.1 Introduction 141
6.2 Limitations and Opportunities in MEMS Fabrication 142
6.3 Benefits of Inkjet in MEMS Fabrication 143
6.4 Chemical Sensors 144
6.5 Optical MEMS Devices 147
6.6 Bio-MEMS Devices 151
6.7 Assembly and Packaging 152
6.8 Conclusions 156
Acknowledgements 156
References 156
7. Conductive Tracks and Passive Electronics 159
Jake Reder
7.1 Introduction 159
7.2 Vision 159
7.3 Drivers 160
7.3.1 Efficient Use of Raw Materials 160
7.3.2 Short-Run and Single-Example Production 161
7.3.3 Capital Equipment 162
7.4 Incumbent Technologies 162
7.5 Conductive Tracks and Contacts 162
7.5.1 What Is Conductivity? 162
7.5.2 Conductive Tracks in the Third Dimension 163
7.5.3 Contacts 163
7.6 Raw Materials: Ink 164
7.6.1 Particles 164
7.6.2 Dispersants 168
7.6.3 Carriers (Liquid Media) 170
7.6.4 Other Additives 170
7.7 Raw Materials: Conductive Polymers 172
7.8 Raw Materials: Substrates 172
7.9 Printing Processes 174
7.10 Post Deposition Processing 174
7.10.1 Sintering 174
7.10.2 Protective Layers 175
7.11 Resistors 175
7.12 Capacitors 176
7.13 Other Passive Electronic Devices 176
7.13.1 Fuses, Circuit Breakers, and Switches 176
7.13.2 Inductors and Transformers 177
7.13.3 Batteries 177
7.13.4 Passive Filters 177
7.13.5 Electrostatic Discharge (ESD) 177
7.13.6 Thermal Management 178
7.14 Outlook 178
References 178
8. Printed Circuit Board Fabrication 183
Neil Chilton
8.1 Introduction 183
8.2 What Is a PCB? 183
8.3 How Is a PCB Manufactured Conventionally? 185
8.4 Imaging 185
8.4.1 Imaging Using Phototools 187
8.4.2 Laser Direct Imaging 188
8.5 PCB Design Formats 188
8.6 Inkjet Applications in PCB Manufacturing 189
8.6.1 Introduction 189
8.6.2 Legend Printing 190
8.6.3 Soldermask 194
8.6.4 Etch Resist 195
8.7 Future Possibilities 202
References 205
9. Active Electronics 207
Madhusudan Singh, Hanna M. Haverinen, Yuka Yoshioka and Ghassan E. Jabbour
9.1 Introduction 207
9.2 Applications of Inkjet Printing to Active Devices 211
9.2.1 OLEDs 211
9.2.2 Other Displays 213
9.2.3 Energy Storage Using Batteries and Supercapacitors 214
9.2.4 Photovoltaics 215
9.2.5 Sensors 217
9.2.6 Transistors, Logic, and Memory 219
9.2.7 Contacts and Conductors 221
9.2.8 In Situ Synthesis and Patterning 223
9.2.9 Biological Applications 223
9.3 Future Outlook 224
References 225
10. Flat Panel Organic Light-Emitting Diode (OLED) Displays: A Case Study 237
Julian Carter, Mark Crankshaw and Sungjune Jung
10.1 Introduction 237
10.2 Development of Inkjet Printing for OLED Displays 238
10.3 Inkjet Requirements for OLED Applications 241
10.3.1 Introduction 241
10.3.2 Display Geometry 241
10.3.3 Containment and Solid Content 241
10.4 Ink Formulation and Process Control 243
10.5 Print Defects and Control 246
10.6 Conclusions and Outlook 249
Acknowledgements 250
References 250
11. Radiofrequency Identification (RFID) Manufacturing: A Case Study 255
Vivek Subramanian
11.1 Introduction 255
11.2 Conventional RFID Technology 256
11.2.1 Introduction 256
11.2.2 RFID Standards and Classifications 256
11.2.3 RFID Using Silicon 258
11.3 Applications of Printing to RFID 260
11.4 Printed Antenna Structures for RFID 260
11.4.1 The Case for Printed Antennae 260
11.4.2 Printed RFID Antenna Technology 261
11.4.3 Summary of Status and Outlook for Printed Antennae 262
11.5 Printed RFID Tags 263
11.5.1 Introduction 263
11.5.2 Topology and Architecture of Printed RFID 264
11.5.3 Devices for Printed RFID 267
11.6 Conclusions 273
References 273
12. Biopolymers and Cells 275
Paul Calvert and Thomas Boland
12.1 Introduction 275
12.2 Printers for Biopolymers and Cells 277
12.2.1 Printer Types 277
12.2.2 Piezoelectric Print-Heads 277
12.2.3 Thermal Inkjet Print-Heads 279
12.2.4 Comparison of Thermal and Piezoelectric Inkjet for Biopolymer Printing 279
12.2.5 Other Droplet Printers 280
12.2.6 Rapid Prototyping and Inkjet Printing 281
12.3 Ink Formulation 282
12.3.1 Introduction 282
12.3.2 Printed Resolution 283
12.3.3 Major Parameters: Viscosity and Surface Tension 283
12.3.4 Drying 285
12.3.5 Corrosion 285
12.3.6 Nanoparticle Inks 285
12.3.7 Biopolymer Inks 285
12.4 Printing Cells 289
12.4.1 Cell-Directing Patterns 289
12.4.2 Cell-Containing Inks 289
12.4.3 Effects of Piezoelectric and Thermal Print-Heads on Cells 290
12.4.4 Cell Attachment and Growth 291
12.4.5 Biocompatibility in the Body 292
12.5 Reactive Inks 292
12.6 Substrates for Printing 296
12.7 Applications 297
12.7.1 Tissue Engineering 297
12.7.2 Bioreactors 298
12.7.3 Printed Tissues 298
12.8 Conclusions 299
References 299
13. Tissue Engineering: A Case Study 307
Makoto Nakamura
13.1 Introduction 307
13.1.1 Tissue Engineering and Regenerative Medicine 307
13.1.2 The Third Dimension in Tissue Engineering and Regenerative Medicine 308
13.1.3 The Current Approach for Manufacturing 3D Tissues 309
13.1.4 A New Approach of Direct 3D Fabrication with Live Cell Printing 309
13.2 A Feasibility Study of Live Cell Printing by Inkjet 310
13.3 3D Biofabrication by Gelation of Inkjet Droplets 313
13.4 2D and 3D Biofabrication by a 3D Bioprinter 314
13.4.1 Micro-Gel Beads 314
13.4.2 Micro-Gel Fiber and Cell Printing 315
13.4.3 2D and 3D Fabrication of Gel Sheets and Gel Mesh 316
13.4.4 Fabrication of 3D Gel Tubes 316
13.4.5 Multicolor 3D Biofabrication 316
13.4.6 Viscosity in Inkjet 3D Biofabrication 318
13.5 Use of Inkjet Technology for 3D Tissue Manufacturing 319
13.5.1 Resolution and DOD Color Printing 319
13.5.2 Direct Printing of Live Cells 319
13.5.3 High-Speed Printing 319
13.5.4 3D Fabrication Using Hydrogels 320
13.5.5 Linkage to Digital Data Sources 321
13.5.6 Applicability to Various Materials including Humoral Factors and Nanomaterials 321
13.5.7 Use of Pluripotent Stem Cells in Bioprinting 322
13.6 Summary and Future Prospects 322
Acknowledgements 323
References 323
14. Three-Dimensional Digital Fabrication 325
Bill O’Neill
14.1 Introduction 325
14.2 Background to Digital Fabrication 326
14.3 Digital Fabrication and Jetted Material Delivery 329
14.4 Liquid-Based Fabrication Techniques 330
14.4.1 PolyJet™: Objet Geometries 330
14.4.2 ProJet™: 3D Systems 333
14.4.3 Solidscape 3D Printers 333
14.5 Powder-Based Fabrication Techniques 335
14.5.1 ZPrinter™: Z Corporation 335
14.5.2 Other Powder-Based 3D Printers 338
14.6 Research Challenges 338
14.7 Future Trends 340
References 341
15. Current Inkjet Technology and Future Directions 343
Mike Willis
15.1 The Inkjet Print-Head as a Delivery Device 343
15.2 Limitations of Inkjet Technology 344
15.2.1 Jetting Fluid Constraints 344
15.2.2 Control of Drop Volume 345
15.2.3 Variations in Drop Volume 345
15.2.4 Jet Directionality and Drop Placement Errors 345
15.2.5 Aerodynamic Effects 347
15.2.6 Impact and Surface Wetting Effects 348
15.3 Today’s Dominant Technologies and Limitations 348
15.3.1 Thermal DOD Inkjet 348
15.3.2 Piezoelectric DOD Inkjet 350
15.4 Other Current Technologies 351
15.4.1 Continuous Inkjet 351
15.4.2 Electrostatic DOD 351
15.4.3 Acoustic Drop Ejection 352
15.5 Emerging Technologies 353
15.5.1 Stream 353
15.5.2 Mems 354
15.5.3 Flextensional 356
15.5.4 Tonejet 356
15.6 Future Trends for Print-Head Manufacturing 357
15.7 Future Requirements and Directions 358
15.7.1 Customisation of Print-Heads for Digital Fabrication 358
15.7.2 Reduce Sensitivity of Jetting to Ink Characteristics 359
15.7.3 Higher Viscosities 359
15.7.4 Higher Stability and Reliability 360
15.7.5 Drop Volume Requirements 360
15.7.6 Lower Costs 361
15.8 Summary of Status of Inkjet Technology for Digital Fabrication 361
References 362
Index 363
About the Author :
Ian Hutchings is Professor of Manufacturing Engineering at the University of Cambridge. He is also Principal Investigator for the EPSRC and industry-funded project on Next Generation Inkjet Technology: A major UK collaborative initiative.
Dr Graham Martin is currently Director for the Inkjet Research Centre at Cambridge University, and prior to this he spent many years in the inkjet industry.
