Polymer-Based Additive Manufacturing (eBook)

Preface 6
Contents 8
Contributors 10
Chapter 1: Polymer-Based Additive Manufacturing: Historical Developments, Process Types and Material Considerations 13
1.1 Introduction 14
1.2 Stereolithography (SLA) 15
1.3 Fused Filament Fabrication 20
1.4 Selective Laser Sintering (SLS) 24
1.5 Freeformer 26
1.6 InkJet Techniques 29
1.7 Laminated Object Manufacturing 29
1.8 Summary 30
References 31
Chapter 2: Design for Additive Manufacturing 35
2.1 Introduction 36
2.2 Design for Manufacturing and Assembly 37
2.3 Advantages of Additive Manufacturing as a Production Process 40
2.3.1 Product Digitisation and Rapid Prototyping 40
2.3.2 Topology Optimisation 41
2.3.3 Geometrical Design Freedom at Low Cost 42
2.3.4 Product Customisation 43
2.3.5 Product Consolidation 44
2.3.6 Lightweight Structures 44
2.3.7 Integrated Functions and Internal Features 46
2.3.8 Multiple Material Builds 46
2.3.9 Optimisation of Supply Chain and Inventory 47
2.4 Suitability of Additive Manufacturing 48
2.5 Product Design Considerations 48
2.5.1 Additive Technology Selection 49
2.5.2 Material Selection 50
2.5.3 Layer Height 50
2.5.4 Support Structures 51
2.5.5 Build Orientation 52
2.5.6 Overhangs and Unsupported Features 53
2.5.7 Hole Design 54
2.5.8 Hollow Sections and Escape Holes 54
2.5.9 Thin Features 55
2.5.10 Geometric Tolerances and Surface Quality 55
2.6 Post-processing 55
2.6.1 Material Removal 56
2.6.2 Surface Finishing and Improving Geometrical Tolerances 57
2.7 Product Consolidation and Weight Saving Using Additive Manufacturing 58
2.8 Chapter Summary 60
References 61
Chapter 3: Mechanics Modeling of Additive Manufactured Polymers 63
3.1 Introduction 64
3.2 Nonlinear Modeling of Additive Manufactured Photopolymers 66
3.2.1 Finite Strain Anisotropic Model for Plastics 67
3.2.2 Anisotropic Hyperelastic Model for Elastomers 72
3.3 Modeling of Shape Memory Photopolymers 74
3.3.1 Background of Shape Memory Polymers 74
3.3.2 Model Descriptions 75
3.3.3 Additive Manufactured Shape Memory Structures 78
3.4 Summary 80
References 81
Chapter 4: Additive Manufacturing of Tooling for Use in Mass Production Processes 84
4.1 Introduction 85
4.2 Technologies 86
4.2.1 Injection Moulding 86
4.2.2 Blow Moulding 89
4.3 Cooling 90
4.3.1 Benefits of Optimised Cooling System Design 91
4.3.2 Conformal Cooling 92
4.4 Comparison of UV Photocurable AM Resin Tools to Metal AM Tools 94
4.5 Benefits of Using Resin-Based Rapid Tools for Injection Moulding 96
4.6 Rapid Tooling: Case Studies 99
4.6.1 Design Verification Through the Use of Resin-Based Tooling 99
4.6.2 Resin-Based Rapid Tooling to Reduce Costs and Lead Times 100
4.6.3 Ceramic-Polymer Tooling Inserts for Use in the Production of Electrical Switch Components 101
4.6.4 Comparison of Resin-Based Printed Tooling to Metal Tooling 101
4.6.5 Comparison of Service Life of Tools Using Different Resins 102
4.6.6 Carbon Fibre-Reinforced Rapid Tooling Inserts 103
4.7 Limitations of Polymer-Based Rapid Tooling 103
4.8 Summary 104
References 105
Chapter 5: Current Market for Biomedical Implants 108
5.1 Introduction 109
5.2 Additive Manufacturing of Biomedical Implants 110
5.2.1 3D-Printed Skin Substitutes 110
5.2.1.1 Materials for Skin Substitutes 111
5.2.1.2 Bioprinting of Skin Substitutes 112
5.2.1.3 Electronic Skin 114
5.2.2 AM of Cardiovascular Stents 115
5.2.2.1 Materials for Cardiovascular Stents 116
5.2.2.2 3D Printing of Cardiovascular Stents 116
5.2.3 3D-Printed ENT (Ear, Nose and Throat) 117
5.2.3.1 Ear 117
5.2.3.2 Nose 120
5.2.3.3 Throat 122
5.2.4 Dental Applications 123
5.3 Summary 124
References 125
Chapter 6: Orthopaedic 3D Printing in Orthopaedic Medicine 131
6.1 Introduction 132
6.2 Patient-Specific Implants 132
6.3 Orthopaedic Applications of 3D Printing 134
6.3.1 Bone Fixation Devices 134
6.3.2 Craniomaxillofacial 138
6.3.3 3D Printing for the Repair of Pelvis Fractures 140
6.3.4 3D Printing in Bone Tissue Engineering 141
6.3.5 3D-Printed Fixtures and Jigs for Surgical Applications 142
6.4 Summary 146
References 147
Chapter 7: Customised Interventions Utilising Additive Manufacturing 153
7.1 Introduction 153
7.2 Pharmaceutical Applications of Additive Manufacturing 156
7.3 Soft Tissue Engineering Applications of Additive Manufacturing 162
7.4 Conclusion 165
References 165
Chapter 8: 3D Bioprinting Hardware 171
8.1 Introduction 172
8.2 Microextrusion 172
8.2.1 Working Principles 173
8.2.2 Associated Hardware 176
8.2.3 Technique Evaluation 177
8.3 Droplet-Based Bioprinting 178
8.3.1 Ink-Jet Bioprinting 179
8.3.1.1 Thermal Drop-on-Demand 179
8.3.1.2 Piezoelectric Drop-on-Demand 180
8.3.1.3 Microvalve Bioprinting 181
8.3.2 Acoustic Bioprinting 181
8.3.3 Electrohydrodynamic Jetting 182
8.3.4 Technique Evaluation 184
8.4 Laser-Assisted Bioprinting 184
8.4.1 Volatilisation Methods 185
8.4.1.1 Laser-Induced Forward Transfer (LIFT) 185
8.4.1.2 Matrix-Assisted Pulsed Laser Evaporation Direct Writing (MAPLE DW) 186
8.4.1.3 Absorbing Film-Assisted Laser-Induced Forward Transfer (AFA-LIFT) and Biological Laser Processing (BioLP™) 186
8.4.2 Laser-Guided Methods 188
8.4.3 Technique Evaluation 188
8.5 Lithography Bioprinting 189
8.5.1 Working Principles 189
8.5.2 Photopolymerisation of Cell-Laden Hydrogels 190
8.6 Summary 191
References 191
Chapter 9: Bioinks and Their Applications in Tissue Engineering 197
9.1 Introduction 198
9.2 Naturally Derived Bioinks 199
9.2.1 Alginate-Based Bioinks 199
9.2.2 Collagen-Based Bioinks 200
9.2.3 Gelatin-Based Bioinks 201
9.2.4 Fibrin-Based Bioinks 201
9.2.5 ECM-Based Bioinks 202
9.3 Synthetic Bioinks 202
9.3.1 Polyethylene Glycol (PEG) 203
9.3.2 Poly(N-isopropylacrylamide) (PNIPAAM) 203
9.3.3 Pluronic 203
9.4 Cell Fate in Printed Constructs 204
9.4.1 Bioink Stiffness 204
9.4.1.1 Fibre-Reinforced Hydrogels 206
9.4.1.2 Interpenetrating Networks Hydrogels 207
9.4.1.3 Double Networks Hydrogels 207
9.4.2 Bioink Composition 208
9.4.2.1 ECM-Based and/or Functionalised Bioinks 208
9.4.2.2 Nanocomposite Bioinks 210
9.4.2.3 Multibioink Strategies 210
9.4.3 Delivery of Signalling Factors 211
9.4.3.1 Homogeneous Immobilisation of Molecules 211
9.4.3.2 Heterogeneous Immobilisation of Molecules 212
9.5 Strategies Towards the Bioprinting of Functional Tissues and Organs 213
9.5.1 Bioprinting Musculoskeletal Tissues 213
9.5.1.1 Bone 213
9.5.1.2 Cartilage 214
9.5.1.3 Composite Tissues 215
9.5.2 Bioprinting Vascular Tissue 216
9.5.2.1 The Incorporation of Seeded and Unseeded Perfusable Channels 216
9.5.2.2 Direct Printing of Cell Patterning 218
9.5.3 Emerging Applications 219
9.5.3.1 Liver 219
9.5.3.2 Disease Models 220
9.6 Summary 220
References 221
Chapter 10: Post-processing Considerations for Biomedical 3D Printing of Polymers 229
10.1 Introduction 229
10.2 Medical AM Industry 232
10.3 Support Removal 233
10.3.1 Loose Support 233
10.3.2 Solid Supports 234
10.3.3 Solvent Washing 235
10.3.4 Ultrasonic Bath 235
10.3.5 Centrifugal Force Cleaning 236
10.4 Post-curing Methods for Polymers 236
10.4.1 Ultraviolet (UV) Curing of Photopolymers 237
10.4.2 Thermal Curing and Heat Treatment of Polymer AM Parts 238
10.5 Testing of Material Properties in AM Parts 239
10.6 Surface Finishing of Polymers 240
10.6.1 Standards for Surface Finish of AM Parts 240
10.6.2 Methods of Surface Finishing 241
10.6.2.1 Mechanical Abrasion Techniques 241
10.6.2.2 Electroplating 242
10.6.2.3 Solvent Vapour Smoothing 243
10.6.2.4 Organic Coatings: Painting, Priming 243
10.6.2.5 Dyeing of Additively Made Polymer Parts 243
10.6.2.6 Surface Textured Parts Directly from CAD (Computer-Aided Design) 244
10.7 Sterilisation Process Considerations for AM Products 245
10.8 Design Considerations for Post-processing of AM Manufactured Devices 246
10.8.1 Design for Post-processing Operations 247
10.8.2 Design for Surface Roughness/Fatigue 247
10.8.3 Design for Solvent Washing 247
10.8.4 Design for Thermal and UV Curing 248
10.8.5 Design for Inspection 248
10.8.6 Design Parts for Safe AM Processing and Post-processing 248
10.9 Design Tolerances for AM Polymer Material 249
10.10 Summary 250
References 251
Chapter 11: Regulatory Considerations for Devices Manufactured Using Additive Manufacturing Technologies 252
11.1 Introduction 252
11.2 Conformity Assessment 253
11.3 Medical Device Classification 254
11.4 Current Regulation Requirements Regarding Additive Manufacturing Devices 255
11.5 Custom-Made Medical Devices 257
11.6 Changes to Mass-Produced Medical Devices and Their Manufacturing Processes 259
11.7 Additive Manufacturing Device Performance Testing Considerations 259
11.8 Conformity Assessment Procedure for Custom-Made Device 261
11.9 Summary 262
References 263
Chapter 12: Additive Manufacturing: Future Challenges 264
12.1 Introduction 264
12.2 Process 266
12.3 Design 267
12.4 Metrology 268
12.5 Materials 269
12.6 Business Models 270
12.7 Dangers of Technology Development 272
12.8 Summary 273
References 273
Index 274