Sample Pages Andreas Gebhardt, Jan
Sample Pages
Andreas Gebhardt, Jan-Steffen Hötter
Additive Manufacturing
3D Printing for Prototyping and Manufacturing
Book ISBN: 978-1-56990-582-1
eBook ISBN: 978-1-56990-583-8
For further information and order see
www.hanserpublications.com (in the Americas)
www.hanser-fachbuch.de (outside the Americas)
© Carl Hanser Verlag, München
Contents
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V
About the Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VII
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Basics, Definitions, and Application Levels . . . . . . . . . . . . . . . . . . IX
1
1.1 Systematics of Manufacturing Technologies . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Systematics of Layer Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.1 Application of Layer Technology: Additive Manufacturing
and 3D Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2.2 Characteristics of Additive Manufacturing . . . . . . . . . . . . . . . . . . 3
1.3 Hierarchical Structure of Additive Manufacturing Processes . . . . . . . . . 6
1.3.1 Rapid Prototyping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3.2 Rapid Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.3.2.1 Rapid Manufacturing—Direct Manufacturing . . . . . . . . . . 9
1.3.2.2 Rapid Manufacturing—Rapid Tooling (Direct Tooling—
Prototype Tooling) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.3.3 Related Nonadditive Processes: Indirect or Secondary Rapid
­Prototyping Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.3.4 Rapid Prototyping or Rapid Manufacturing? . . . . . . . . . . . . . . . . . 11
1.3.5 Diversity of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.3.6 How Fast Is Rapid? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.4 Integration of Additive Manufacturing in the Product Development
Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.4.1 Additive Manufacturing and Product Development . . . . . . . . . . . 13
1.4.2 Additive Manufacturing for Low-Volume and One-of-a-Kind
Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
1.4.3 Additive Manufacturing for Individualized Production . . . . . . . . 15
1.5 Machines for Additive Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
XII
Contents
2 Characteristics of the Additive Manufacturing Process . . . . . . 21
2.1 Basic Principles of the Additive Manufacturing Process . . . . . . . . . . . . . 21
2.2 Generation of Layer Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.2.1 Description of the Geometry by a 3D Data Record . . . . . . . . . . . . 26
2.2.1.1 Data Flow and Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.2.1.2 Modeling 3D Bodies in a Computer by Means of 3D CAD 28
2.2.1.3 Generating 3D Models from Measurements . . . . . . . . . . . 32
2.2.2 Generation of Geometrical Layer Information on Single Layers . 33
2.2.2.1 STL Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.2.2.2 CLI/SLC Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
2.2.2.3 PLY and VRML Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
2.2.2.4 AMF Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
2.3 Physical Principles for Layer Generation . . . . . . . . . . . . . . . . . . . . . . . . . . 44
2.3.1 Solidification of Liquid Materials . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.3.1.1 Photopolymerization―Stereolithography (SL) . . . . . . . . . . 45
2.3.1.2 Basic Principles of Polymerization . . . . . . . . . . . . . . . . . . 46
2.3.2 Generation from the Solid Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
2.3.2.1 Melting and Solidification of Powders and Granules:
Laser Sintering (LS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
2.3.2.2 Cutting from Foils: Layer Laminate Manufacturing (LLM) 65
2.3.2.3 Melting and Solidification out of the Solid Phase:
Fused Layer Modeling (FLM) . . . . . . . . . . . . . . . . . . . . . . . 66
2.3.2.4 Conglutination of Granules and Binders: 3D Printing . . . 69
2.3.3 Solidification from the Gas Phase . . . . . . . . . . . . . . . . . . . . . . . . . . 71
2.3.3.1 Aerosol Printing Process . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
2.3.3.2 Laser Chemical Vapor Deposition (LCVD) . . . . . . . . . . . . . 72
2.3.4 Other Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
2.3.4.1Sonoluminescence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
2.3.4.2Electroviscosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
2.4 Elements for Generating the Physical Layer . . . . . . . . . . . . . . . . . . . . . . . 74
2.4.1 Moving Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
2.4.1.1Plotter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
2.4.1.2Scanner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
2.4.1.3 Simultaneous Robots (Delta Robots) . . . . . . . . . . . . . . . . . 76
2.4.2 Generating and Contouring Elements . . . . . . . . . . . . . . . . . . . . . . . 76
2.4.2.1Laser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
2.4.2.2Nozzles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
2.4.2.3Extruder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
2.4.2.4 Cutting Blade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
2.4.2.5 Milling Cutter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
2.4.3 Layer-Generating Element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Contents
2.5 Classification of Additive Manufacturing Processes . . . . . . . . . . . . . . . . . 84
2.6 Summary Evaluation of the Theoretical Potentials of Rapid Prototyping
­Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
2.6.1Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
2.6.2 Model Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
2.6.3Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
2.6.4Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
2.6.5 Surface Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
2.6.6 Development Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
2.6.7 Continuous 3D Model Generation . . . . . . . . . . . . . . . . . . . . . . . . . . 91
3 Machines for Rapid Prototyping, Direct Tooling, and Direct
­Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
3.1 Polymerization: Stereolithography (SL) . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
3.1.1 Machine-Specific Basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
3.1.1.1 Laser Stereolithography . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
3.1.1.2 Digital Light Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
3.1.1.3 PolyJet and MultiJet Modeling and Paste Polymerization 108
3.1.2 Overview: Polymerization, Stereolithography . . . . . . . . . . . . . . . . 108
3.1.3 Stereolithography Apparatus (SLA), 3D Systems . . . . . . . . . . . . . 110
3.1.4 STEREOS, EOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
3.1.5 Stereolithography, Fockele & Schwarze . . . . . . . . . . . . . . . . . . . . . 121
3.1.6 Microstereolithography, microTEC . . . . . . . . . . . . . . . . . . . . . . . . . 122
3.1.7 Solid Ground Curing, Cubital . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
3.1.8 Digital Light Processing, Envisiontec . . . . . . . . . . . . . . . . . . . . . . . 126
3.1.9 Polymer Printing, Stratasys/Objet . . . . . . . . . . . . . . . . . . . . . . . . . . 132
3.1.10 Multijet Modeling (MJM), ProJet, 3D Systems . . . . . . . . . . . . . . . . 137
3.1.11 Digital Wax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
3.1.12 Film Transfer Imaging, 3D Systems . . . . . . . . . . . . . . . . . . . . . . . . 143
3.1.13 Other Polymerization Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
3.1.13.1 Paste Polymerization, OptoForm . . . . . . . . . . . . . . . . . . . . 146
3.2 Sintering/Selective Sintering: Melting in the Powder Bed . . . . . . . . . . . 146
3.2.1 Machine-Specific Basic Principles . . . . . . . . . . . . . . . . . . . . . . . . . . 146
3.2.2 Overview: Sintering and Melting . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
3.2.3 Selective Laser Sintering, 3D Systems/DTM . . . . . . . . . . . . . . . . . 153
3.2.4 Laser Sintering, EOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
3.2.5 Laser Melting, Realizer GmbH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
3.2.6 Laser Sintering, SLM Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
3.2.7 Laser Melting, Renishaw Ltd. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
3.2.8 Laser Cusing, Concept Laser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
3.2.9 Direct Laser Forming, TRUMPF . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
XIII
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Contents
3.2.10 Electron Beam Melting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
3.2.11 Selective Mask Sintering (SMS), Sintermask . . . . . . . . . . . . . . . . . 197
3.2.12 Laser Sintering, Phenix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
3.3 Coating: Melting with the Powder Nozzle . . . . . . . . . . . . . . . . . . . . . . . . . 203
3.3.1 Process Principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
3.3.1.1 Concepts of Powder Nozzles . . . . . . . . . . . . . . . . . . . . . . . . 205
3.3.1.2 Process Monitoring and Control . . . . . . . . . . . . . . . . . . . . 206
3.3.2 Laser-Engineered Net Shaping (LENS), Optomec . . . . . . . . . . . . . . 206
3.3.3 Direct Metal Deposition (DMD), DM3D Technology (TRUMPF) . . 209
3.4 Layer Laminate Manufacturing (LLM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213
3.4.1 Overview of Layer Laminate Manufacturing . . . . . . . . . . . . . . . . . 213
3.4.2 Machine-Specific Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
3.4.3 Laminated Object Manufacturing (LOM), Cubic Technologies . . . 218
3.4.4 Rapid Prototyping Systems (RPS), Kinergy . . . . . . . . . . . . . . . . . . 223
3.4.5 Selective Adhesive and Hot Press Process (SAHP), Kira . . . . . . . . 224
3.4.6 Layer Milling Process (LMP), Zimmermann . . . . . . . . . . . . . . . . . . 225
3.4.7 Stratoconception, rp2i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
3.4.8 Paper 3D Printing, MCor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
3.4.9 Plastic Sheet Lamination, Solido . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
3.4.10 Other Layer Laminate Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231
3.4.10.1 Parts of Metal Foils: Laminated Metal Prototyping . . . . . 231
3.5 Extrusion: Fused Layer Modeling (FLM) . . . . . . . . . . . . . . . . . . . . . . . . . . 232
3.5.1 Overview of Extrusion Processes . . . . . . . . . . . . . . . . . . . . . . . . . . 232
3.5.2 Fused Deposition Modeling (FDM), Stratasys . . . . . . . . . . . . . . . . 233
3.5.3 Wax Printers, Solidscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
3.5.4 Multijet Modeling (MJM), ThermoJet, 3D Systems . . . . . . . . . . . . 247
3.6 Three-Dimensional Printing (3DP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
3.6.1 Overview: 3D Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
3.6.2 3D Printer, 3D Systems, and Z Corporation . . . . . . . . . . . . . . . . . . 248
3.6.3 Metal and Molding Sand Printer, ExOne . . . . . . . . . . . . . . . . . . . . 253
3.6.3.1 Metal Line: Direct Metal Printer . . . . . . . . . . . . . . . . . . . . 255
3.6.3.2 Molding Sand Line: Direct Core and Mold-Making
Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
3.6.4 Direct Shell Production Casting (DSPC), Soligen . . . . . . . . . . . . . . 259
3.6.5 3D Printing System, Voxeljet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
3.6.6 Maskless Mesoscale Material Deposition (M3D), Optomec . . . . . 267
3.7 Hybrid Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269
3.7.1 Controlled Metal Buildup (CMB) . . . . . . . . . . . . . . . . . . . . . . . . . . . 270
3.7.2 Laminating and Ultrasonic Welding: Ultrasonic Consolidation,
Solidica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Contents
3.8 Summary Evaluation of Rapid Prototyping Processes . . . . . . . . . . . . . . . 276
3.8.1 Characteristic Properties of AM Processes Compared
to Conventional Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
3.8.2Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279
3.8.3Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
3.8.4 Benchmark Tests and User Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
3.9 Planning Targets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 288
3.10Follow-up Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
3.10.1 Target Material: Plastics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 289
3.10.2 Target Material: Metal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 290
4 Rapid Prototyping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
4.1 Classification and Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
4.1.1 Properties of Prototypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
4.1.2 Characteristics of Rapid Prototyping . . . . . . . . . . . . . . . . . . . . . . . 292
4.2 Strategic Aspects for the Use of Prototypes . . . . . . . . . . . . . . . . . . . . . . . . 293
4.2.1 Product Development Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
4.2.2 Time to Market . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
4.2.3 Front Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295
4.2.4 Digital Product Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
4.2.5 The Limits of Physical Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
4.2.6 Communication and Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . 300
4.3 Operational Aspects in the Use of Prototypes . . . . . . . . . . . . . . . . . . . . . . 301
4.3.1 Rapid Prototyping as a Tool for Fast Product Development . . . . . 301
4.3.1.1Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
4.3.1.2 Model Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 302
4.3.1.3 Model Classes and Additive Processes . . . . . . . . . . . . . . . 305
4.3.1.4 Assignment of Model Classes and Model Properties
to the Families of Additive Production Processes . . . . . . 309
4.3.2 Applications of Rapid Prototyping in Industrial Product
­Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312
4.3.2.1 Example: Housing of a Pump . . . . . . . . . . . . . . . . . . . . . . . 312
4.3.2.2 Example: Office Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
4.3.2.3 Example: Recessed Lighting Socket . . . . . . . . . . . . . . . . . . 317
4.3.2.4 Example: Model Digger Arm . . . . . . . . . . . . . . . . . . . . . . . 318
4.3.2.5 Example: LCD Projector . . . . . . . . . . . . . . . . . . . . . . . . . . . 322
4.3.2.6 Example: Capillary Bottom for Flower Pots . . . . . . . . . . . . 323
4.3.2.7 Example: Casing for a Coffeemaker . . . . . . . . . . . . . . . . . . 324
4.3.2.8 Example: Intake Manifold of a Four-Cylinder Engine . . . 325
4.3.2.9 Example: Cocktail Glass . . . . . . . . . . . . . . . . . . . . . . . . . . . 326
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4.3.3
4.3.4
4.3.5
4.3.6
4.3.2.10Example: Mirror Triangle . . . . . . . . . . . . . . . . . . . . . . . . . . 327
4.3.2.11 Example: Convertible Top . . . . . . . . . . . . . . . . . . . . . . . . . . 327
Rapid Prototyping Models for the Visualization of 3D Data . . . . . 331
Rapid Prototyping in Medicine . . . . . . . . . . . . . . . . . . . . . . . . . . . . 332
4.3.4.1 Characteristics of Medical Models . . . . . . . . . . . . . . . . . . . 332
4.3.4.2 Anatomic Facsimile Models . . . . . . . . . . . . . . . . . . . . . . . . 333
4.3.4.3 Example: Anatomic Facsimiles for a Reconstructive
Osteotomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 335
Rapid Prototyping in Art, Archaeology, and Architecture . . . . . . . 336
4.3.5.1 Model Making in Art and Design, General . . . . . . . . . . . . 336
4.3.5.2 Example of Art: Computer Sculpture, Georg Glückman . 337
4.3.5.3 Example of Design: Bottle Opener . . . . . . . . . . . . . . . . . . . 337
4.3.5.4 Applied Art: Statuary and Sculpture . . . . . . . . . . . . . . . . . 339
4.3.5.5 Example of Archaeology: Bust of Queen Teje . . . . . . . . . . 340
4.3.5.6 Model Building in Architecture, General . . . . . . . . . . . . . 341
4.3.5.7 Example of Architecture: German Pavilion at Expo ’92 . . 342
4.3.5.8 Example of Architecture: Ground Zero . . . . . . . . . . . . . . . 342
4.3.5.9 Example of Architectural Monuments: Documentation
of Buildings Relevant to Architectural History . . . . . . . . 344
Rapid Prototyping for the Evaluation of Calculation Methods . . . 345
4.3.6.1 Photoelastic and Thermoelastic Stress Analysis . . . . . . . 345
4.3.6.2 Example: Photoelastic Stress Analysis for a Cam Rod
in the Engine of a Truck . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
4.3.6.3 Example: Thermoelastic Stress Analysis for Verifying
the Stability of a Car Wheel Rim . . . . . . . . . . . . . . . . . . . . 349
4.4Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352
5 Rapid Tooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
5.1 Classification and Definition of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
5.1.1 Direct and Indirect Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354
5.2 Properties of Additive Manufactured Tools . . . . . . . . . . . . . . . . . . . . . . . . 355
5.2.1 Strategic Aspects for the Use of Additive Manufactured Tools . . 356
5.2.1.1Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356
5.2.1.2 Implementation of New Technical Concepts . . . . . . . . . . . 356
5.2.2 Design Properties of Additive Manufactured Tools . . . . . . . . . . . . 358
5.2.2.1 Prototype Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358
5.2.2.2 Supply of Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
5.3 Indirect Rapid Tooling Processes: Molding Processes and Follow-up
Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
5.3.1 Suitability of AM Processes for the Manufacture of
Master Patterns for Subsequent Processes . . . . . . . . . . . . . . . . . . 363
Contents
5.3.2 Indirect Methods for the Manufacture of Tools for
Plastic Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
5.3.2.1 Casting in Soft Tools or Molds . . . . . . . . . . . . . . . . . . . . . . 365
5.3.2.2 Casting into Hard Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370
5.3.2.3 Other Molding Techniques for Hard Tools . . . . . . . . . . . . 374
5.3.3 Indirect Methods for the Manufacture of Metal Components . . . 375
5.3.3.1 Investment Casting with AM Process Steps . . . . . . . . . . . 375
5.3.3.2 Tools by Investment Casting of Rapid Prototyping
Master Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378
5.4 Direct Rapid Tooling Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
5.4.1 Prototype Tooling: Tools Based on Plastic Rapid Prototyping
­Models and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
5.4.1.1 ACES Injection Molding . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
5.4.1.2 Deep Drawing or Thermoforming . . . . . . . . . . . . . . . . . . . 380
5.4.1.3 Casting of Rapid Prototyping Models . . . . . . . . . . . . . . . . 381
5.4.1.4 Manufacture of Cores and Molds for Metal Casting . . . . . 382
5.4.2 Metal Tools Based on Multilevel AM Processes . . . . . . . . . . . . . . . 383
5.4.2.1 Selective Laser Sintering of Metals: IMLS by 3D Systems 383
5.4.2.2 Paste Polymerization: OptoForm . . . . . . . . . . . . . . . . . . . . 384
5.4.2.3 3D Printing of Metals: ExOne . . . . . . . . . . . . . . . . . . . . . . . 384
5.4.3 Direct Tooling: Tools Based on Metal Rapid Prototype Processes 385
5.4.3.1 Multicomponent Metal Powder Laser Sintering . . . . . . . . 385
5.4.3.2 Single-Component Metal Powder Methods: Sintering
and Additive Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . 386
5.4.3.3 Laser Generating with Powder and Wire . . . . . . . . . . . . . 391
5.4.3.4 Layer Laminate Process, Metal Blade Tools, Laminated
Metal Tooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
5.5 Future Prospects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394
6 Direct Manufacturing: Rapid Manufacturing . . . . . . . . . . . . . . . . . 395
6.1 Classification and Definition of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
6.1.1Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396
6.1.2 From Rapid Prototyping to Rapid Manufacturing . . . . . . . . . . . . . 397
6.1.3 Workflow for Direct Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . 398
6.1.4 Requirements for Direct Manufacturing . . . . . . . . . . . . . . . . . . . . . 398
6.2 Potential for Additive Manufacturing of End Products . . . . . . . . . . . . . . . 399
6.2.1 Increased Design Freedom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
6.2.1.1 Advanced Design and Structural Opportunities . . . . . . . 399
6.2.1.2 Functional Integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400
6.2.1.3 Novel Design Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 401
6.2.2 Production of Traditionally Not Producible Products . . . . . . . . . . 401
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XVIII Contents
6.2.3 Variation of Mass Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
6.2.4 Personalization of Mass Products . . . . . . . . . . . . . . . . . . . . . . . . . . 403
6.2.4.1 Passive Personalization: Manufacturer Personalization . 404
6.2.4.2 Active Personalization: Customer Personalization . . . . . . 406
6.2.5 Realization of New Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407
6.2.6 Realization of New Manufacturing Strategies . . . . . . . . . . . . . . . . 407
6.2.7 Design of New Labor and Living Alternatives . . . . . . . . . . . . . . . . 408
6.3 Requirements on Additive Manufacturing for Production . . . . . . . . . . . . 409
6.3.1 Requirements on Additive Manufacturing of a Part . . . . . . . . . . . 410
6.3.1.1Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 410
6.3.1.2Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411
6.3.1.3Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
6.3.1.4Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413
6.3.1.5 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
6.3.1.6Logistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
6.3.2 Requirements for Additive Mass Production with
Current ­Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 414
6.3.2.1Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415
6.3.2.2Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
6.3.2.3Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417
6.3.2.4Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
6.3.2.5 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
6.3.2.6Logistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 418
6.3.3 Future Efforts in Additive Series Production . . . . . . . . . . . . . . . . . 418
6.3.3.1Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
6.3.3.2Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
6.3.3.3Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
6.3.3.4Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422
6.3.3.5 Quality Assurance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423
6.3.3.6Logistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 424
6.4 Implementation of Rapid Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . 424
6.4.1 Additive Manufacturing Machines as Elements of a
­Process Chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425
6.4.2 Additive Machines for Complete Production of Products . . . . . . . 426
6.4.2.1 Industrial Complete Production . . . . . . . . . . . . . . . . . . . . . 426
6.4.2.2 Individual Complete Production (Personal Fabrication) . 428
6.5 Application Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 429
6.5.1 Application Fields for Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . 430
6.5.1.1 Metallic Materials and Alloys . . . . . . . . . . . . . . . . . . . . . . . 430
6.5.1.2 High-Performance Ceramics . . . . . . . . . . . . . . . . . . . . . . . . 431
Contents
6.5.1.3Plastics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 432
6.5.1.4 New Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433
6.5.2 Application Fields by Industry . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433
6.5.2.1Tooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433
6.5.2.2Casting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 435
6.5.2.3 Medical Equipment and Aids, Medical Technology . . . . . 438
6.5.2.4 Design and Art . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443
6.6Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448
7 Safety and Environmental Protection . . . . . . . . . . . . . . . . . . . . . . . 451
7.1 Labor Agreements for the Operation and Production of Additive Manu­
facturing Machines and the Handling of the Corresponding Material . . 452
7.2 Annotations to Materials for Additive Manufacturing . . . . . . . . . . . . . . . 453
7.3 Annotations for Using Additive Manufactured Components . . . . . . . . . . 454
8 Economic Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457
8.1 Strategic Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458
8.1.1 Strategic Aspects of the Use of AM Methods in Product
­Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458
8.1.1.1 Qualitative Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458
8.1.1.2 Quantitative Approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . 459
8.2 Operative Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 460
8.2.1 Establishing the Optimal Additive Manufacturing Process . . . . . 460
8.2.2 Establishing the Costs of Additive Manufacturing Processes . . . 461
8.2.2.1 Variable Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 462
8.2.2.2 Fixed Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464
8.2.3 Characteristics of Additive Manufacturing and Its Impacts
on Economy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467
8.2.3.1 Construction Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467
8.2.3.2 Lot Sizes and Use of Construction Space . . . . . . . . . . . . . 467
8.2.3.3Utilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
8.2.3.4 Material Consumption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468
8.2.3.5 Process Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469
8.2.3.6 Construction Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469
8.2.3.7 Technical Progress and Model Refinement . . . . . . . . . . . . 471
8.2.3.8Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 471
8.3 Make or Buy? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 472
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Contents
9 Future Rapid Prototyping Processes . . . . . . . . . . . . . . . . . . . . . . . . 475
9.1Microcomponents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475
9.1.1 Microcomponents Made of Metal and Ceramic . . . . . . . . . . . . . . . 475
9.1.2 Microcomponents Made of Metal and Ceramics by Laser Melting 476
9.1.2.1 Melting Process in Selective Laser Melting . . . . . . . . . . . 476
9.1.2.2 Microstructures of Metal Powder . . . . . . . . . . . . . . . . . . . . 477
9.1.2.3 Microstructures of Ceramic Powder . . . . . . . . . . . . . . . . . 480
9.2 Contour Crafting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482
9.3 D-Shape Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 484
9.4 Selective Inhibition of Sintering (SIS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487
9.4.1 The SIS-Polymer Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 487
9.4.2 The SIS-Metal Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
9.5 Free Molding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 491
9.6Freeformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492
10 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 569
11 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 575
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 581
Foreword
Since the late 1980s, in fact, for more than 25 years, Additive Manufacturing (AM)
has been penetrating the world of manufacturing. When the layer-based technology emerged, it was called Rapid Prototyping (RP). This was the best name for a
technology that could not fabricate anything but sticky and brittle parts, which
could only be used as prototypes. The process was not even “rapid,” although it
­allowed the making of time- and money-consuming tools to be avoided. With the
creation of the first prototype by RP, a significant amount of time and money could
be saved.
The initial process was called stereolithography and it was based on photo-polymerization, which first processed acrylates and then epoxies later on. In the following
years, new layer-based processes were developed and an extended range of materials became qualified for AM applications, and all of them were plastics.
Around the turn of the millennium, processes for making metal parts were introduced to the market. With this development, the focus of manufacturers as well
as of the users changed from just prototyping to manufacturing because of improved processes, materials, software, and control. The challenge was then to make
final parts.
Today all classes of engineering materials, such as plastics, metals, ceramics, and
even nontraditional materials, such as food, drugs, human tissue, and bones, can
be processed using 3D printers.
There is still a long way to go, but due to vibrant activities concerning all aspects of
3D printing worldwide, this high-speed development is incomparable to the expansion of any fabrication technology in the past.
There are two main reasons for intense interesting in this technology for somebody
active in the field of product development and production:
First, to stay competitive, one should be able to judge the capabilities of existing,
new, and emerging AM processes in comparison to traditional manufacturing processes and process chains. The task is not just a matter of speeding up the process
but to improve the way we do engineering design towards “designing for AM.” This
VI
Foreword
makes completely new products possible and shifts the competition of traditional
manufacturing towards a new level of lightweight design, as well as resource-­
saving and environmentally friendly mass production of individual parts.
Second, people begin to understand that AM is not just capable of revolutionizing
our way of designing and producing parts, but able to affect many aspects of our
daily lives.
AM touches upon legal aspects, such as product reliability and intellectual property rights, as compared to the digital entertainment market. AM also brings even
more challenges as parts can cause significant problems like physical injuries or
even death, which music and videos do not do.
Digital data, including not only technical data such as a blue print, but the exact
information for creating the product, can easily be sent all over the world and encounter every imaginable hurdle, such as frontiers, embargos, custom fees, export
regulations, and many more. This requires us to rethink the well-functioning world
of today.
Many of the questions raised, if not the majority, need to be decided by people who
are not technicians. The better that those involved understand the technical part
and the more thorough their information, the better decisions they will be qualified to make.
Consequently, this book was written to support the product developers and people
who are responsible for the production, as well as others who are involved in the
process of realizing the enormous challenges of this technology.
Aachen in March 2016
Andreas Gebhardt
1
Basics, Definitions,
and Application Levels
To understand the characteristics and the capabilities of additive manufacturing
(AM), it is very helpful to take a look at the systematics of manufacturing technologies in general first.
„„1.1 Systematics of Manufacturing
Technologies
Orientated on the geometry only, manufacturing technology in general is divided
into three fundamental clusters [Burns, 93, AMT, 14]:1
1.subtractive manufacturing technology,
2.formative manufacturing technology, and
3.additive manufacturing technology.
With subtractive manufacturing technology, the desired geometry is obtained by
the defined removal of material, for example, by milling or turning.
Formative manufacturing means to alter the geometry in a defined way by applying external forces or heat, for example, by bending, forging, or casting. Formative
manufacturing does not change the volume of the part.
Additive manufacturing creates the desired shape by adding material, preferably
by staggering contoured layers on top of each other. Therefore it is also called layer
(or layered) technology.
The principle of layer technology is based on the fact that any object, at least theoretically, can be sliced into layers and rebuilt using these layers, regardless of the
complexity of its geometry.
In Germany, manufacturing technology is divided into six main categories, and each of them is subdivided
into various subcategories [DIN 8580], [Witt, 06].
1
21 Basics, Definitions, and Application Levels
Figure 1.1 underlines this principle. It shows the so-called sculpture puzzle, in
which a three-dimensional (3D) object has to be assembled from more than 100
slices. Therefore the layers have to be arranged vertically in the right sequence
using a supporting stick.
Figure 1.1 Principle of layer technology, example: sculpture puzzle
(Source: HASBRO/MB Puzzle)
Additive manufacturing (AM) is an automated fabrication process based on layer
technology. AM integrates two main subprocesses: the physical making of each
single layer and the joining of subsequent layers in sequence to form the part.
Both processes are done simultaneously. The AM build process just requires the
3D data of the part, commonly called the virtual product model.
It is a characteristic of AM that not only the geometry but the material properties
of the part as well are generated during the build process.
„„1.2 Systematics of Layer Technology
In this section the commonly used terms in AM are addressed. The related characteristics as well as their interdependency and the hierarchical structure are discussed.
In this book the generally accepted so-called generic terms are used, and alternatively used names are mentioned.
1.2 Systematics of Layer Technology
Generic terms and brand names have to be distinguished from each other. If they
are mixed, which happens quite often, this frequently leads to confusion. As brand
names are important in practice, they are addressed, explained, and linked to the
generic terms in Chapter 3, where the AM machines are presented.
1.2.1 Application of Layer Technology: Additive Manufacturing
and 3D Printing
Additive manufacturing is the generic term for all manufacturing technologies that
automatically produce parts by physically making and joining volume elements,
commonly called voxels. The volume elements are generally layers of even thickness.
Additive manufacturing is standardized in the US (ASTM F2792) and in Germany
(VDI 3405), and is commonly used worldwide.
As alternative terms, additive manufacturing (technology) and additive layer
­manufacturing (ALM) have minor acceptance.
3D printing is about to replace all other names, including additive manufacturing,
and to become the generally accepted generic term for layer technology in the near
future. This is mainly because it is very easy to understand. Everyone who can
operate a text editor (a word processor) and a 2D office printer easily understands
that he or she will be able to print a 3D object using a 3D design program (a part
processor) and a 3D printing machine, regardless of how it works.
NOTE: Additive manufacturing and 3D printing are used as equal generic terms in
this book. While in Chapter 1 this is expressed by always writing additive manufacturing /3D printing (or AM/3DP). In the following chapters only additive manufacturing or AM is used in order to shorten the text volume.
Beginners should realize that 3D Printing is also the brand name of a family of
powder binder processes (see Section 3.6), originally developed by MIT and ­licensed
to Z-Corporation (now 3D Systems), Voxeljet, and others.
1.2.2 Characteristics of Additive Manufacturing
Layer technologies in general and additive manufacturing in particular show special characteristics:
ƒƒThe geometry of each layer is obtained solely and directly from the 3D compu­teraided design (CAD) data of the part (commonly called a virtual product model).
ƒƒThere are no product-related tools necessary and consequently no tool change.
ƒƒThe material properties of the part are generated during the build process.
3
41 Basics, Definitions, and Application Levels
ƒƒThe parts can be built in any imaginable orientation. There is no need for clamping, thus eliminating the clamping problem of subtractive manufacturing technologies. Nevertheless, some processes need support structures, and the orientation of the part influences the parts’ properties.
ƒƒToday, all AM processes can be run using the same so-called STL (or AMF) data
structure, thus eliminating data exchange problems with preprocessors as used
in subtractive manufacturing.
Additive manufacturing/3D printing therefore ensures the direct conversion of the
3D CAD data (the virtual product model) into a physical or real part.
As scaling can be done simply in the CAD file, parts of different sizes and made
from different materials can be obtained from the same data set. As an example,
the towers of a chess set shown in Fig. 1.2 are based on the same data set but made
with different AM machines and from different materials. The range of materials
includes foundry sand, acrylic resin, starch powder, metals, and epoxy resin.
Figure 1.2 Additive manufacturing. Scaled towers of a chess set, based on the same data set
but made with different AM machines and from different materials.
Small towers, from left to right: PMMA (powder-binder process, Voxeljet), metal (laser sintering,
EOS), acrylate, transparent (stereolithography, Envisiontec; height approx. 3 cm).
Big towers, from left to right: foundry sand (powder-binder process, Voxeljet), starch powder
(powder-binder process, 3D Systems; height approx. 20 cm) (Source: machine manufacturers)
One of the biggest AM parts of all is the tower shown in Fig. 1.3 with a height of
approximately 2.5 m, which is higher than the general manager of the Voxeljet
Company, Mr. I. Ederer.
1.2 Systematics of Layer Technology
Figure 1.3 Chess tower made from foundry sand, height approx. 2.5 m, powder-binder
­process (Source: Voxeljet)
By contrast, Fig. 1.4 shows a tower made by micro laser sintering. It is approximately 5 mm high.
Figure 1.4 Tower made from metal, height approx. 5 mm, micro laser sintering
(Source: EOS/3D Micromac)
AM/3DP allows manufacturing of geometric details that cannot be made using
subtractive or formative technologies. As an example, the towers on Fig. 1.2 contain spiral staircases and centered double-helix hand rails. The details can be seen
on a cutaway model displayed in Fig. 1.5.
5
61 Basics, Definitions, and Application Levels
Figure  1.5 Internal details of the rear right tower on Fig. 1.2
(Source: 3D Systems)
Another example of geometries that cannot be manufactured using subtractive or
formative technologies is shown in Fig. 2.5.
All AM/3DP processes mentioned here will be explained in detail in Chapter 3.
„„1.3 Hierarchical Structure of Additive
Manufacturing Processes
For a proper definition of the terms used, it is very helpful to distinguish the technology and its application from each other. Subtractive manufacturing, for example, marks the technology level, and drilling, grinding, milling, and so on are the
names for its application (or the application level).
The technology of additive manufacturing/3D printing is divided in two main application levels: rapid prototyping and rapid manufacturing. Rapid prototyping is
the application of AM/3DP to make prototypes and models or mock-ups, and rapid
manufacturing is the application to make final parts and products.
The manufacturing of tools, tool inserts, gauges, and so on usually is called rapid
tooling. The term often is regarded as an independent hierarchical element or application level, but effectively it is not. Depending on how a tool is made, it represents a prototype or a product (Fig. 1.6).
Prototyping
Additive Manufacturing
3D Printing
Manufacturing
Application
Technology
1.3 Hierarchical Structure of Additive Manufacturing Processes
Rapid Prototyping
Rapid
Tooling
Rapid Manufacturing
Manufacturing of
- Concept Models
- Functional Prototypes
Manufacturing of
tools and tool inserts
Manufacturing of
final parts
Figure 1.6 Basic structure of additive manufacturing/3D printing technology and its
­subcategories rapid prototyping, rapid manufacturing, and rapid tooling
1.3.1 Rapid Prototyping
Rapid prototyping (RP) is the application of AM/3DP technology to make prototypes, models, and mock-ups, all of them being physical parts but not products.
They only mimic isolated properties of the latter product in order to verify the
­engineering design and to allow the testing of selected product capabilities and
thus to improve and speed up the product development process. The goal is to preplan a part to make it as simple as possible in order to get it quickly and cheaply.
Therefore, rapid prototyping parts generally cannot be used as final products.
As prototypes differ from products, serial identical prototypes (which are not products but prototypes) do not exist, although the term is used to underline a strategy.
Rapid prototyping again is subdivided into solid imaging or concept modeling, and
functional prototyping.
Solid imaging or concept modeling: If a rapid prototyping part is made mainly for 3D
visualization, it is called a solid image, a concept model, a mock-up, or even a rapid
mock-up. The idea behind it is to generate a 3D picture or a statue (Fig. 1.7). To
highlight this aspect, the parts are also called show-and-tell models.
If a part has a single or some of the functionalities of the latter product, it can be
used to verify this aspect of the engineering design. Consequently it is called a
functional prototype (and the process functional prototyping accordingly).
7
81 Basics, Definitions, and Application Levels
Non-Additive
Processes
Rapid Prototyping
Solid Imaging
Concept Modeling
Functional
Prototyping
Prototype
Tooling
Rapid Manufacturing
Direct Tooling
Rapid
Tooling
Prototyping
Additive Manufacturing
3D Printing
Manufacturing
Application
Technology
Additive Processes
Direct Manufacturing
Indirect
Prototyping
Indirect Tooling
Indirect
Manufacturing
Figure 1.7 Basic structure of the AM/3D printing technology: application levels rapid prototyping, rapid manufacturing, and rapid tooling and its subcategories
A sample of each category is displayed in Fig. 1.8. The scaled data control model of
a convertible roof system (made from polyamide by laser sintering) can be regarded as a typical concept model. The air-outlet nozzle of a passenger car (made
by laser stereolithography from epoxy resin) is a functional prototype that supports the testing of the car’s climate control.
Figure 1.8 Rapid prototyping: concept model or solid image (left), laser sintering (Source: CP
GmbH); functional prototype (right), laser stereolithography (Source: 3D Systems)
The corresponding AM processes are presented in detail in Chapter 3.
1.3 Hierarchical Structure of Additive Manufacturing Processes
1.3.2 Rapid Manufacturing
Rapid manufacturing (RM) names the application of the AM/3D printing technology to make final parts or products, often called series products, even if they are
one-offs. (A deeper discussion can be found in Chapter 6.) The parts can be positives like connectors as well as negatives like cavities. Making positives or parts is
called direct manufacturing, and the additive manufacturing of negatives or cavities, such as tools and tool inserts, is called direct tooling; see Fig. 1.7.
1.3.2.1 Rapid Manufacturing—Direct Manufacturing
Additive manufacturing or 3D printing of final parts or products is called direct
manufacturing (DM). Frequently and for historical reasons it is also called rapid
manufacturing (RM) and complies directly with the main term. Often the terms
e-manufacturing, digital manufacturing, tool-less fabrication, and others are used.
Direct manufacturing is based on the same technology as rapid prototyping and, at
least until today, uses the same machines. The goal is to make final products.
Whether the goal can be reached or not depends on the degree of accomplishment
of the required mechanical and technological properties. This again depends on
the machines, processes, and materials available. Further, whether the needed accuracy can be reached and if a competitive price can be achieved are essential.
As an example of direct manufacturing, Fig. 1.9 shows a three-element dental
bridge (left). The associated process chain will be shown in Chapter 3, and applications will be discussed in Chapter 6.
Figure 1.9 Rapid manufacturing: direct manufacturing of a three-element dental bridge (left)
(Source: GoetheLab FH Aachen/Sokalla); direct tooling for making golf balls (right) (Source:
EOS GmbH)
9
342 Characteristics of the Additive Manufacturing Process
2.2.2.1 STL Format
In order to obtain an STL data set of the part, the surfaces of the part are approximated by triangles. Volume elements exhibit at least two surfaces, the inner and
outer surfaces. Both of them differ only by the normal vectors. The definition of the
surface by triangles is called triangulation or tessellation. This leads to the socalled STL data. It is regarded as a de facto industry standard for AM processes, but
it is actually nowhere standardized.
This contributed to the fact that this process, long before it was discovered for
­additive manufacturing, was used for shading and thus for the visualization of
three-dimen­sional CAD lattice models. Decisive for the establishment of the STL
format as an interface for additive manufacturing was the early publication of the
interface formulation. The STL interface, which has been known since then as the
ste­reolithography interface, could be used by both machine manufacturers and
free software businesses. This was especially beneficial to the development of special software that is offered by independent developers and made a lasting contribution to the user-friendliness of additive manufacturing systems.
The STL data contains the normal vector (positive direction outward, away from
the volume) and the coordinates of the three vertices of each triangle (Fig. 2.9). An
ASCII or binary file can be created. The amount of data is much lower for binary
files, but ASCII files are comparatively easy to read and control in the source code.
Figure 2.9 shows such a triangle patch and the corresponding ASCII data set per
triangle enclosed by the commands FACET and ENDFACET.
Figure 2.9 Definition of triangle patches in STL format and the associated ASCII data set
[Hoffmann, 95] [BRITE/EuRAM, 94]
2.2 Generation of Layer Information
Figure 2.10 shows the triangular patches coated on a real component, called the
triangulated surface.
Figure 2.10 Triangulated surface and associated manufactured component
(Source: 3D ­Systems)
The STL formulation, however, possesses practical advantages:
Given that the surface is based on triangles, it is possible to cut the model at any
desired z coordinate. Also, when the CAD model is not available, STL models permit any desired scale at random without reversing into the CAD.
Because the intersection contains only data elements of a type that can be described by relatively simple means, syntax errors of the ASCII version in the programming of the interface are very easy to recognize and eliminate, and therefore
they pose practically no problem.
In contrast to contour-oriented intersections, smaller errors may be repaired relatively easily. It is also an advantage that a triangle provides a higher quality of
geo­metric information than does the contour vector.
The STL formulation also has disadvantages:
ƒƒIt generates a large volume of data, especially when the surface quality is improved by refining the net of triangles.
ƒƒSTL files contain only geometrical information. Information about color, texture,
material, or other characteristics of the physical model are missing.
35
362 Characteristics of the Additive Manufacturing Process
2.2.2.1.1 Errors in STL Files
During the transformation of the CAD internal geometry data into STL files, different errors can occur that affect the quality of the physical component. The errors
are categorized by Hoffmann [Hoffmann, 95] as
ƒƒconstruction errors,
ƒƒtransforming errors, and
ƒƒdescription errors.
Construction errors are based on unnecessary data inside the component that are
the result of combining the single elements incorrectly in the CAD system
(Fig. 2.11). These errors are problematic for the AM process. For example, LLM
processes include unnecessary cuts because of these errors. The consequences
range from additional expenses during the building process to the total loss of the
part. Construction errors do not affect components that are produced by polymerization and sintering processes.
Figure 2.11 Effects of merged faulty geometric bodies [Hoffmann, 95]
Transforming errors exist when the convergence of the mathematically exact contour (as provided by the CAD) by triangles is inaccurate and the number of transforming errors is larger the lower the number of triangles chosen. In Fig. 2.12(a),
this fundamental secant error is demonstrated in the example of errors appearing
in the convergence of a circle by (f/4), eight (f/8), and twelve (f/12) secants. Figure 2.12(b) shows the consequences on the modeling of a globe surface.
2.2 Generation of Layer Information
f/4
f/8
f/12
(a)
(b)
Figure 2.12 (a) Secant error at the approach of a circle by 4 (f/4), 8 (f/8), or 12 (f/12) line segments; (b) Influence of the number of triangles in the modeling of the surface of a sphere (STL)
With the increased accuracy in defining the surface made possible by increasing
the number of triangles, the amount of data increases enormously. In one published example the growth factor was 22 [Donahue, 91]. Critics continually cite
this as one of the disadvantages of the STL formulation. Although this is correct in
principle, it should be remembered that if alternative processes are used, for example the contour-oriented formulation, the closed curves must also be displayed as
polygonal drawings and the amount of data resulting from this kind of representation also grows enormously with the growing demand for accuracy.
In practical terms, the fineness of the triangulation is not problematic if approved
settings are used.
Description errors are primarily attributable to three causes:
1.gaps between triangle patches (boundary error),
2.double triangle patches (overlap), and
3.incorrect orientation of individual patches (disorientation).
Figure 2.13 shows this error schematically.
Correct
Orientation
Patch 5
Patch 1
Gap
Patch 2
Patch 3
Patch 4
Patch 5
Patch 1
Overlap
Patch 6
Patch 2
Patch 3
Patch 4
Patch 5
Patch 1
Patch 2
Patch 3
Patch 4
Wrong
Orientation
Gap
Overlap
Figure 2.13 Description error: gap, overlap, and incorrect orientation
Misorientation
37
382 Characteristics of the Additive Manufacturing Process
Gaps (and double triangle patches as a special form of gaps) are the result of inaccurate boundaries that border on each other. The existence of differing resolution
densities of geometries can cause boundary errors on the edge on the opposite
side. These are called “naked edges.”
Such defects are irrelevant for visualization and also for processing with cutter
­diameters in the range of millimeters. In applications with lasers that exhibit a
beam diameter of 0.1 mm, such defects have a negative effect. Description errors
make the production process difficult or in some cases impossible.
When the surface is oriented incorrectly, the normal vector points to the inside of
the model. In general, the human eye can assign such surfaces correctly, but for
generating machine data these results are problematic. The result is that the inner
and outer sides cannot be separated (Fig. 2.13).
When the machine-specific layer information is generated, all gaps have to be
closed. This process is called the repair of the data set. Normally, special modules
of front-end software do this automatically. While repairing semiautomatically,
manual intervention leads to faster and better results.
Repairing data are limited. The sample shown in Fig. 2.14(a) still allows for an easy
repair. On the other hand, Fig. 2.14(b) shows a sample that is likely not fixable. The
best solution for such errors is to avoid mistakes during the construction phase of
the CAD model.
Cross Section
Zb
Za
Cross-sectional Layer (Plane)
(a)
(b)
Figure 2.14 Influence of imperfectly bordered deterministic surface models on the production
of layer models
2.2.2.2 CLI/SLC Format
The CLI (SLI, SLC) interface, also called the contour-oriented interface, assumes
the geometry data for each individual layer of the component that is to be produced. In this case the CLI (common layer interface) interface is a cross-system,
742 Characteristics of the Additive Manufacturing Process
this process would bring the great advantage that the UV radiation necessary for
polymerization would not need to penetrate a material layer of a certain thickness
and thereby reducing its strength; it could instead be generated directly at the required point of polymerization. Spatial structures could be constructed by such
sound fields and their interferences.
2.3.4.2 Electroviscosity
Electroviscosity is the ability of certain materials to alter their viscosity within
broad limits while under the influence of powerful electromagnetic fields. This can
go so far that liquids completely solidify. The process is not yet in use in commercial industry, primarily because the increase in viscosity cannot be produced technically and economically over a longer period of time. However, this method opens
new perspectives for additive manufacturing processes. Electroviscosity enables
liquids to be solidified along a defined 3D curve that can be calculated using potential equations. They form thereby a continuous contour that can be filled in with
photosensitive or other rapidly solidifying materials. This can be done within a
relatively short time. After solidification, the contour is removed by liquefaction
and, on the basis of the new contour calculated from theoretical potential equations, another part of the model can be generated. Such a process opens the possibility of working entirely in 3D, but it depends, at least according to current knowledge, on theoretically calculated three-dimensional potential curves.
„„2.4 Elements for Generating the Physical
Layer
2.4.1 Moving Elements
The moving element defines the geometry of the component. Therefore it has to
generate the inner and outer contours of each layer and if necessary, the intervening space. It demands high movement speeds and also a high path accuracy and
repeatability. A (galvo) scanner or (x-y) plotter and sometimes combinations of
both are used.
2.4.1.1 Plotter
Plotters are essentially x-y-positioning systems with separate axes. Timing belts
and racks are used as drivers. Plotters are available in different sizes having characteristic dimensions in a range of a few millimeters to several meters. The variety
is too large to be treated here in detail. The building platforms of most additive
2.4 Elements for Generating the Physical Layer
manufacturing machines have characteristic dimensions of several hundreds of
millimeters. Plotters used in the cutting operation nowadays have the following
technical data: cutting speeds between 10 and 100 mm/s (tangential plotters in the
diagonal area to 1500 mm/s) and more; repeat accuracies of ± 0.1 mm; and pressing forces from about 0 to 600 grams.
2.4.1.2 Scanner
Scanners or galvos are freely programmable deflection systems that move the laser
beam on the building plane. The term galvo merely refers to a motor-driven mirror
unit rotating around its longitudinal axis according to the galvanometer principle,
and is only one element of a scanner unit. Two galvos are aligned orthogonal to one
another (one each for the x and y directions) to reach every point on the build platform. In this arrangement, the focus describes in fact a spherical shell. The projection is therefore in the center of the building plane, and with increasing distance it
becomes increasingly blurred, especially so in the corners of the building space.
The answer to the blurriness is a so-called F-theta or flat-field lens that provides
the focus outside the optical axis. The focus therefore remains for any deflection in
one building plane.
Figure 2.33 shows the scanning optics, consisting of the beam expander, two motorized galvo mirrors, and the F-theta lens. The arrangement of the galvo in front
of the flat-field lens is also called preobjective scanning.
Figure  2.33 Scanning optics for imaging of the layer information on the building plane, consisting of the
beam, two galvo mirrors, and an F-theta lens
The mirrors shall be lightweight to allow fast scanning speeds. To achieve fast
scanning speeds, their mass inertia can be reduced by cutting off the corners,
which gives them their characteristic shape. Mirrors are advantageously made of
single-crystal silicon as a substrate material and a coating with the lowest possible
absorption losses. The coating must be matched to the laser wavelengths used.
75
762 Characteristics of the Additive Manufacturing Process
The trend is to use laser scanners with digital servo electronics. This is possible
due to an improved encoder with a significantly improved dynamic response and
increased accuracy. The electronics also allows communication between the system controller and the scanner and thereby enables online diagnostic procedures.
2.4.1.3 Simultaneous Robots (Delta Robots)
Delta robots are a variant of the parallel robots. There are three universal joints
fixed to the frame-mounted rotary axes. The result is a spatial parallelogram guiding the moving element and the contouring element (the effector). This new design
has only been used in the Delta Rostock fabber (Fig. 2.34). There the contouring
element is an extrusion nozzle. Delta robots are relatively simple in construction,
light, and fast. Their accuracy is sufficient for fabber applications.
Figure 2.34 Delta Rostock fabber with parallel kinematics
2.4.2 Generating and Contouring Elements
Generating elements generate the layer. Depending on the process, the elements
also do the contouring.
The elements differ in that there may or may not be a mechanical interaction with
the layer. Laser and nozzles are among the noncontact processes (nonimpact). The
cutting blades, milling cutter, and to a lesser extent, the extruder, place mechanical
forces on the component. These are called impact processes.
2.4 Elements for Generating the Physical Layer
2.4.2.1 Laser
The laser is of special importance in prototyping because of its ability to focus a
high energy density onto an extremely small operating diameter. Especially in connection with the scanners for the polymerization, melting, or vaporizing (cutting)
of materials, it can be necessary to introduce energy with high positioning and
tracking accuracy and repeatability that can produce pinpoint accuracy.
Depending on the absorption behavior of the materials, lasers with different wavelengths are used.
For the cutting of paper or plastics or the sintering or melting of plastics, a CO2 laser (wavelength 10,600 nm) is preferred.
Polymerization requires a laser at wavelengths below 500 nm. For the processing
of metals, even shorter wavelengths are advantageous.
Ar++ ion and HeCd lasers were the first lasers used in machines because of their
favorable wavelengths despite their poor efficiency, and were used until the late
1990s. Today only solid-state lasers are installed in machines. Thus, the efficiency
and the service life are significantly improved and the age-related gradual decline
in performance largely eliminated.
The latest designs, such as diode-pumped solid-state lasers or disk or fiber lasers,
have significantly contributed to improving the beam quality and dynamics. Today
with fiber lasers, beam diameters in the range of 20 to 50 microns are realized. In
addition, the beam cross section can be varied quickly with adjustable optical elements and thus reduced for boundaries and enlarged for filling areas. An elaboration of the laser principle, which due to the few types of lasers that were preferred
for use in additive manufacturing production in 2000, was located in the appendix
to the German second edition of this book. Given the numerous types that are used
today, this has been omitted. A comprehensive current representation with a focus
on production with lasers can be found for example in Poprawe [Poprawe, 04].
We differentiate between three processes when projecting the geometrical layer
information onto the layer: vector, raster, and mask processes. The basic principles
of these methods are also found in other contouring processes; for example, the
vector process is used in cutting plotters when knives are in action. Masks can also
be used in the process of using lamps or projectors for polymerization. The vector
process uses either a (mirror) scanner or x-y plotters. In the vector process, the
single contour elements are generated continuously from basic geometric elements
such as straight lines, circular arcs, and so forth on the basis of the standardized
plotter software. It can be assumed, therefore, that a circular contour parallel to the
layer will appear as a polygonal curve in the STL formulation and as a continuous
circle in the SLC formulation. The laser beam can be pulsed, as in most polymerization and sintering processes (the processes are discussed in Section 2.3), or work
continuously (continuous wave, CW), as in layer laminate processes. The vector
77
782 Characteristics of the Additive Manufacturing Process
process is the most accurate process, but also the slowest. The duration of the generation of a layer depends in particular on the complexity of the layer.
In the raster process, the contour is still generated using the same geometric information, but—as with an older television picture—line by line. As a result, a stair-stepping effect appears from line to line similar to that in the z direction. The height of
the steps is determined by the width of the effective track, and in the case of a laser, by the width of the laser beam. As the effective width of the laser beam may be
up to 0.3 mm. Such raster processes will, for nonrectangular geometries, have a
much higher tendency to generate a stair-stepping effect in the layer surface than
that of the design-dependent layers in the z surface. The vector process enables the
contour to be moved by half a beam diameter (beam width compensation), resulting in very accurate contourings; the raster process cannot do this. The duration of
the generation of a layer in the raster process does not depend on the complexity of
the layer. The process is faster than the vector process, but slower than the mask
process.
The third possibility is the mask process. Here a mask is produced to be geometrically similar but on a smaller scale and is then screened by an energy source. As
with a diapositive, an authentic-scale contour is reproduced on the layer surface.
The accuracy is limited by the precision with which the mask can be made. Mask
processes operate with transparent, electrostatically or sequentially coated masks
for LCD (liquid crystal display) technology monitors or directly with DLP (digital
light processing) projectors, but also with mechanical masks. The exposure of an
entire layer occurs all at once. The exposure time is therefore not dependent on the
complexity of the layer, and the process operates quickly.
Figure 2.35 shows the three principal processes for the reproduction of the geo­
metric layer information onto the layer.
(a)
(b)
(c)
Figure 2.35 (a) Vector, (b) raster, and (c) mask processes to image the geometric information
onto the layer
2.4 Elements for Generating the Physical Layer
2.4.2.2 Nozzles
Bubble-Jet or Thermal Nozzles
A bubble-jet print head is composed of an ink reservoir that is connected through
a capillary with the actual nozzle (Fig. 2.36). The ink channel is electrically heated
shortly before the nozzle. As a result, the ink vaporizes locally. The resulting vapor
bubble abruptly displaces a defined volume of ink that is fed due to the pressure
conditions through the nozzle onto the print destination. In the case of additive
manufacturing it is sprayed on the powder bed.
Figure 2.36 Principle of bubble-jet nozzles. (Source: Tecchannel (www.tecchannel.de))
In a print head, up to several hundred nozzles can be accommodated per print
head, with the nozzle having diameters of about 20 to 50 microns. The drop volume is approximately 4 to 30 picoliters, and the temperature at the heating element is 300°C. The thermal system is comparatively slow. A frequency of about
4 kHz is standard, with about 10 kHz as the upper limit. The Photo-Ret-III process
of Hewlett-Packard reaches a frequency of approximately 18 kHz. From 408 nozzles, approximately 7.3 million droplets per second are applied with a volume of
5 picoliters. However, the process prints 29 points, one above the other, and has
been optimized for 2D printing on paper or foil.
It is often considered a disadvantage of thermal print heads that the drop size cannot be varied. That is not true. By sequential heating, preferably by two downstream heaters connected in series, two different-sized vaporization zones can be
created with appropriate tuning, which joins into one and thus carries away a significant amount of liquid. However, it is very difficult to form very different large
drops. In addition, the drop rate is quite low. Thermal print heads for 2D printing
are usually replaced together with the ink reservoir so that the wear of the nozzle
does not affect the print result in practice. Each color (cyan, magenta, yellow, and
black) may have its own reservoir and head, or an integrated head may be used for
all colors, depending on the manufacturer and the use of the device. There are also
systems with separate nozzles and reservoirs.
79
802 Characteristics of the Additive Manufacturing Process
In the integration of printing systems in additive manufacturing machines, larger
amounts of fluid have to be used, and the controllers are modified accordingly.
Therefore, the standard ink reservoirs are replaced with binder tanks that are connected via tubing systems. The commercial print heads of 2D printers are usually
used as nozzles.
Piezo Nozzle
A pure (electro)mechanical process can be more precise and especially faster than
a thermal controlled one. The deformation occurs in approximately 5 microseconds, the reverse deformation as well, so frequencies up to 30 kHz can be achieved.
The droplet size can be adjusted by the applied voltage and quickly varied. The ink
channels and hence the drop volume are smaller (2 pl (pL)) than in thermal systems, so a point diameter of 0.035 microns can be achieved on the paper, which
corresponds to a resolution of 800 dpi. Currently, the mechanical positioning systems set the limits more than the print heads.
Figure 2.37 Principle of a piezo nozzle. (Source: Tecchannel (www.tecchannel.de))
With a piezo nozzle, highly viscous liquids and binders that are thermally sensitive
can also be processed. Moreover, an independent preheating of the fluid is possible.
Thus is created the optimal conditions for additive manufacturing machines that can
print photopolymers or other high-viscosity fluids. Coinciding with the “firing” of a
droplet, a negative pressure can be generated by applying a negative voltage to the
piezo quartz in the ink channel. The result is that the ink is pulled back slightly at
the nozzle. This “meniscus” effect (drastic pull ejection meniscus control) also causes
a bias of the droplet surface, which favors the “firing” of the next droplet and at the
same time suppresses the formation of secondary droplets.
Piezo heads are especially sensitive to air or gas inclusions, because due to its compressibility, the impulse needed for ejection can be resorbed (or absorbed). The
problem corresponds to the case of the venting of water pipes. Piezo elements and
their control usually require more space than thermal jets. Therefore a typical
2.4 Elements for Generating the Physical Layer
­ iezo print head has fewer nozzles (50 to 100, maximum 200) than does a thermal
p
print head.
Piezo heads are robust but also more expensive than thermal print heads. They are
not usually exchanged in printers, but are static and therefore also optimally adjusted. When refilling the ink there is no risk of maladjustment. Today’s systems
usually still have replaceable print heads because of the higher wear in additive
manufacturing machines. Particularly maintenance-friendly designs offer replaceable single nozzles or nozzle groups.
Accuracy
The minimum droplet size can define the accuracy of a printing process in combination with the positioning in the y direction (row direction) and in the x direction
(line spacing). High-quality printing requires a correspondingly high repeatability.
The system also includes very high mechanical requirements.
Powder-binder systems are also limited in their accuracy by the size of the powder
particles. Common are particle sizes of 50 microns (up to 100 µm). The lower limit
is approximately 20 microns. When colored components are produced by such systems and their texture is defined by the binder, the surface shows after a possible
grinding operation for finishing large areas of colored powder. At preferably white
powder the component accordingly appears in pastel colors.
Materials
The different inks should not be discussed at this point because this happens later
in the description of the individual machines. However, the development of a 2D
printing technique that has primarily UV-stable colors as a goal should be pointed
out. In this context, RCP colors (radiation curable pigmented inks) are developed
whose coloring constituents polymerize by UV radiation to stable pigments. This
allows one to print almost all weather-resistant materials. In view of today’s additive ­manufacturing processes that print photopolymers, there arise interesting
perspectives for the production of colored components.
2.4.2.3 Extruder
Extruders used in additive manufacturing operate according to the system of
­constant volume. A geometrically defined material, mostly as a wire but also in the
form of blocks, is placed in an electrically heated chamber. There it is converted by
the heat into the viscous state. The chamber is also called a “liquifier,” although
liquefaction must be avoided in order to achieve a defined material application. A
supplied volume of the same amount is extruded through a nozzle and coated as a
layer onto the component. Nowadays, machines have only one nozzle for the building
material. Because the material is available colored, differently colored components
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822 Characteristics of the Additive Manufacturing Process
can be manufactured. However, the color cannot be changed within one component, so textures cannot be achieved. Because all commercialized extrusion processes work with supports, a second nozzle for the support material is usually installed in the machine. The use of multiple, parallel operating extrusion nozzles is
generally possible but currently only applied by fabbers. There are also constructions that apply differently colored material. For industrial machines this has not
been realized yet. Unlike printing systems, extruders operate quasi-continuously;
in other words, they apply the material in one go, but interrupt the extruding during the positioning phase. The distance between the outlet of the nozzle and the
surface of the component must always be lower than the extruded material cross
section so that the viscous material can be “crimped” on the partially completed
structure. The cross section will become oval. Extruder systems work with little
force, but not entirely without contact. Extrusion systems are very sensitive to air
and gas pockets. Another problem is the water consumption of the building material, which is expressed as vapor bubbles with splashes.
2.4.2.4 Cutting Blade
Contouring with blades draws on the technique of 2D cutting plotters for paper and
film. For this, x-y plotters are used. Cutting speeds of up to 300 mm/s can be
reached. Processes with cutting blades are not nonimpact processes. The blades
reach a pressing force of about 30 to 300 g.
Films made of paper, plastic, and ceramic are preferably contoured with blades. A
cutting resolution of 0.025 mm per step and an accuracy of 0.1 mm (Roland SP
300) can be achieved.
All systems for contouring have in common that not only the characteristics of the
contouring element, for example, the nozzle diameter, the laser beam diameter, or
the width of the blade, but equally also the precision of the x-y (z) handling system
used determine the quality of the component.
2.4.2.5 Milling Cutter
If cutters are used in additive manufacturing, the optionally modified milling machines and processing are not any different from conventional milling. Therefore,
and in view of the large number of possible machine concepts, machining with
milling cutters will not be discussed further. A very extensive and also hands-on
book was written by Degner [Degner, 02]. Schulz [Schulz, 96] describes the aspects of high-speed machining in his book. Wirth [Wirth, 02] describes the model
milling process and practical implementation from the CAD program.
2.4 Elements for Generating the Physical Layer
2.4.3 Layer-Generating Element
An additive manufacturing machine is equipped with moving elements and generating elements that are geared to each other. Together they form the layer-generating
element and thus constitute the additive manufacturing heart of the machine. Just
a few combinations have been proven in practice. Table 2.1 shows the most common combinations. Any other special solutions are discussed with the corresponding machine in Chapter 3.
Table 2.1 Most Common Combinations of Layer-Generating Elements
Physical principle
Section Additive manu­
facturing family
Moving Generating/contouring
element ­element
Photopolymerization
2.3.1.1
Stereolithography
Scanner
Laser
Polymer printing
Plotter
Printing head
Sintering
Scanner
Laser
Melting and solidification of
powders and pellets
2.3.2.1
Cutting from foils/films and
joining
2.3.2.2
LLM
Plotter
Laser, knife, milling tool
Melting and solidification out
of the solid phase
2.3.2.3
FLM
Plotter
Extruder, nozzle
Conglutination of granules
with binders
2.3.2.4
3D Printing
Plotter
Printing head
Generation from the gas
phase
2.3.3.1
Aerosol printing
Plotter
Nozzle
Melting
The layer-generating element is actually the tool of the additive manufacturing
machine. It firmly belongs to the machine and would not change depending on the
component, which is why it is said that additive manufacturing works without
tools. Strictly speaking, they do not need a tool that is individually adapted to the
production task. It is not necessary to change the tool when a skull model and a
radio panel are produced one after the other, just as with a 2D printer: if a notice
is to be printed instead of a commendation, it is not necessary to change the
­machine settings.
Because the layer-generating element has the function of the tool, it is important to
determine and control the parameters that define the operational capability of the
tool and also develop strategies to operate in the allowed parameter fields.
For all elements, the designers make use of additive manufacturing systems that
have preferably been proven on large-series technology. Around 26 million installed inkjet and laser printers form an economically solid basis for the development of applications adapted accordingly. Only through the use of components,
whose development had been financed through sales from other markets, was the
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842 Characteristics of the Additive Manufacturing Process
development of additive manufacturing equipment possible. It is also the only way
to finance it in the future. In about 15 years (1988–2003), additive manufacturing
machines increased to 10,000 systems worldwide.
„„2.5 Classification of Additive
Manufacturing Processes
The professional literature contains a number of different representations concerning the systematics of additive manufacturing processes. Many are oriented
only to the currently available methods or to isolated properties of such processes.
They agree, for the moment, but that quickly reaches the limits when new processes need to be integrated. All additive manufacturing processes (including all
additive manufacturing processes) are in the end manufacturing processes. Therefore their nomenclature should be based on the standardization of the manufacturing processes (DIN 8580).
Additive manufacturing processes are not always unique to a main group due to
their variety. Basically they are in the main group 1, creating cohesion or archetypes (DIN 8581).
As constituent manufacturing processes, they would fall under the aspect “cohesion increasing” assigned to the main group 5 “Coating,” and because of many
variants of the process, assigned to other groups and subgroups. After weighing
the pros and cons, a classification is possible based on the standardization of archetypes (DIN 8581). The additive manufacturing methods are classified in the
first outline level according to the state of aggregation of their original material,
and in the following level, by the appearance in the sense of a semifinished product. In the third level, the mechanism of layer formation is shown, and the fourth
level contains the generic description of the process.
In Fig. 2.38, the current processes can be clearly classified to date while maintaining the proven structure.
The industrial processes and their manufacturers or brand names allocated to the
generic designations are discussed in Chapter 3. There the classification found in
Fig. 2.38 continues, including the industrial processes and their product names.
Section 3.2/3.3
Sintering
Melting
Melt and solidify
Powder
Layer
Laminate process
Section 3.4
Section 3.6
Cut-off
and combine
3D Printing
Glueing with
Binder
Foil/ Plate
Past e
Section 3.1
Polymerization and
Stereolithography
Polymerization
LCVD
Aerosol printing
Section 3.6.6
Chemical
Reaction
Precipitate
Gas
Liquid
Aerosol
Gas
Liquid
Figure 2.38 Classification of additive manufacturing processes depending on aggregate state of the basic material referring to DIN 8580
Section 3.5
Extrusion
processes
Melt and solidify
Wire
Solid
2.5 Classification of Additive Manufacturing Processes
85
4.3 Operational Aspects in the Use of Prototypes
(a)
(b)
(c)
Figure 4.50 Model of the Aachen cathedral, fused deposition modeling. The CAD data were
reconstructed from images and processed for model building: (a) full model, scale around
1 : 468, (b) detail of the roof, with deliberate extrusion structure, (c) important parts of the
building history produced as single parts (Source: FH Aachen/Einhard Gymnasium Aachen)
4.3.6 Rapid Prototyping for the Evaluation of Calculation Methods
4.3.6.1 Photoelastic and Thermoelastic Stress Analysis
Mathematical-physical calculation models allow the simulation of product properties, like stability, vibration behavior, and temperature resistance, and of manufacturing technologies, for example, casting simulations that are based only on theoretical approaches directly at the computer. The use of such methods, which are
also the basis for virtual reality, is the fastest route to new products.
One disadvantage of the calculation models is that they are more or less simplified,
so their results cannot be fully applied on the repetition part and there are more or
less uncertainties. Therefore, the variables of the models have to be changed or
corrected constantly by the results of evaluations, which were carried out on repetition parts. A fast and efficient way to get such correction values is to carry out the
experimental evaluations on rapid prototyping parts instead of repetition parts.
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3464 Rapid Prototyping
A longer-used method is the so-called photoelastic stress analysis on specially developed acrylic glass parts. Polished rapid prototyping models could also be used
here and can enhance the geometric possibilities.
A newer, but also significantly more complex, approach is the detection of the
stress level by a systematic analysis of analogies between the optical and the thermal properties of the part. This method is called thermoelastic stress analysis.
4.3.6.1.1 Photoelastic Stress Analysis
The approach is to use the refraction properties of stereolithography models for
photoelastic analyses and thereby verify the predictions of computer calculations
by testing at an early stage of product development.
Epoxy resins, especially those used for stereolithography, have the property of displaying optical double refractions, which is the basis for a stress analysis aided by
photoelasticity. An interference pattern in the transparent stereolithography component is obtained that is proportional to the stress within the component and that
can be interpreted manually or automatically.
This process adopts the concept of photoelasticity, which has been known since the
beginning of this century. With the aid of stereolithography models, today’s greatest problem can now also be solved—that of making 3D models from conventional
photoelastic materials.
Epoxy resins are exceedingly well suited for the generation of models for photoelasticity because of their high transparency. They hardly differ from the standard
materials (Araldit B, Ciba Geigy) used for photoelasticity. Acrylates are less well
suited because of their lower degree of transparency. If used for stereolithography
models, care should be taken that the model is cured as evenly as possible, so as
few air bubbles as possible are created, and that the surface is flawless. Some
kinds of construction and exposure methods, for example, those generating hollows intentionally to increase the quality and dimensional stability of SL components, are therefore unsuitable for photoelastic checks. It also has to be taken into
account that semipolymerizing processes (whereby complete polymerization occurs later in a postcuring oven) thus create optically effective parting planes. From
the aspect of photoelasticity, components made of epoxy resins SL5170 and SL5180
that use the build style ACES (3D Systems) are especially suitable.
The basic setup for photoelastic checks (Fig. 4.51) consists of a pole filter, a light
source, and two λ/4-wave plates, which facilitate the separation of the isochromatics (lines of the same principal stress difference) from the isoclines (lines of the
same principal stress) so that then only the isochromatics and the transparent
model, which is placed between the two λ/4-plates, can be viewed.
Regardless of the type of resin used, the necessary material parameters must first
be defined before the photoelastic test can be carried out and evaluated. The most
4.3 Operational Aspects in the Use of Prototypes
important value is the photoelastic constant, which is determined from a calibration test and which denotes the relationship between stress and isochromatic order. The photoelastic material parameters of the most important stereolithography
resins are listed in Appendix A3.15, “RP Materials and Casting Resins” [Steinchen,
94]. Should other resins or other kinds of constructions (scan strategies) be used,
these calibration tests ought to be repeated.
Figure 4.51 Setup for a photoelastic stress analysis (Drawing: Steinchen)
4.3.6.1.2 Thermoelastic Stress Analysis
The development of safety-relevant devices such as, for example, steering assembly parts in automobile manufacturing, still relies on tests made on series identical
models. Rapid prototyping processes change little here because the plastic parts
and also modern metal parts can either not be tested under series conditions or, if
tested, they do not allow any applicable conclusions to be drawn.
Thermoelastic stress analysis (THESA) is successfully employed in testing such
components without extensive field trials. It allows single parts to be simulated on
the test bench instead of monitoring the module or doing a driving test. THESA is
based on the fact that metal components under stress show temperature changes
that are proportional to the given stress, provided the load stays within the elastic
sector. These temperature fields and their fluctuations can be recorded using appropriate high-resolution thermal cameras; tensions can be related to the temperature fields and correlated with the strains. This process was modified in cooperation with an automobile manufacturer, so it is now possible to use this process,
initially meant for metal components, for plastic components also [Gartzen, 98]. In
principle, this has paved the way for the optimization of highly stressed components with the aid of plastic rapid prototyping models.
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3484 Rapid Prototyping
4.3.6.2 Example: Photoelastic Stress Analysis for a Cam Rod
in the Engine of a Truck
The starting point is a 3D CAD model of the component to be tested. This is produced as a stereolithography component. Care should be taken that the value of
the photoelastic constant is kept as low as possible. The most important parameter
here is the aftercure under UV light [Steinchen, 94].
Further action depends on whether a 2D test at room temperature is to be run, or a
3D photoelastic test. If a 3D test is required, the stereolithography component must
first be “frozen.” Using an oven with a programmable cooling curve, the model is
heated up to approximately the glass transition temperature, loaded, and then
cooled down to room temperature at 2 to 3 °C per hour. Afterward, the elongations,
and thereby also the tensions, are “frozen.”
The photoelastic test itself is now run on 2D models. In the case of a 3D photoelastic test, this involves the cutting out of a cross section at the test-relevant area for
use as a 2D model. A normal band saw can be used for this purpose.
When placing such a 2D (Fig. 4.52, top) or 3D (Fig. 4.52, middle) model of the valve
lifter (Fig. 4.52, bottom) between two polarizers or quarter-wave plates (Fig. 4.51),
a usable isochromatic pattern is recognizable in the 2D model. For the 3D model of
the valve lifter, the isochromatic images of the single layers are superimposed so
that a clear definition is not readily possible. In general, it can be observed that the
stress concentration is higher the more isochromatics appear at a particular point
and the closer they are together. If the quarter-wave plates are removed, the isoclines are recognizable. Whether an interpretation of the isocline picture is necessary depends on the method of analysis used. An automatic analysis using an electronic image processing system is also possible. The aim of the analysis is to define
the main extensions and the main tensions to allow a conclusion to be drawn concerning the number of tensions.
After the interpretation of the isochromatic picture is complete, the results of the
test can be used for dimensioning prototypes with the aid of similarity laws. The
similarity law for the static case is, for example:
(4.1)
As Equation 4.1 shows, the results are transferable without great effort. To summarize, it can be stated that photoelasticity together with stereolithography is a
reliable and economical method of implementing an experimental optimization of
the subsequent product already in the design phase [Jacobs, 95], [Kramer, 92],
[Susebach, 93], [Steinchen, 94].
4.3 Operational Aspects in the Use of Prototypes
Figure 4.52 Two-dimensional (top) and
three-dimensional (center) model of a valve
lifter (bottom) (Source: Steinchen)
4.3.6.3 Example: Thermoelastic Stress Analysis for Verifying the Stability of
a Car Wheel Rim
The wheel rims of sports cars are highly stressed safety components that are increasingly required to be lightweight and attractive while the dynamic stress on
them increases continuously. A hollow rim promises to fulfill these requirements.
The development is difficult, however, because the prototypes of hollow rim segments cannot be produced by milling as in solid constructions. For optimization
purposes, therefore, the components must be cast as in series processes. One set of
molds is necessary for each casting and has to be made as custom-built models
from wood in a model workshop.
The development until now has been correspondingly complicated (Fig. 4.53, left
string). From the CAD data, which are checked and optimized by FEM processes
(for reasons of clarity, the optimization loop is not shown in the graph), a second
cast in aluminum is obtained by conventional mold making. This cast is finished,
mounted, and tested. Depending on the results, this loop is performed several
times and the results iteratively improved.
349
3504 Rapid Prototyping
CAD
FEM
Traditional
Mold Design
RP-Master
(Polystyrene)
Foundry
RP-Master
(Polyamide)
THESA
Assembly
Test Rig
Traditional
Development Chain
Rapid Development using
RP-Model
RP-Model
and THESA
Figure 4.53 THESA, schematic steps in the process chain and the shortening thereof by the
use of rapid prototyping (Source: Schwarz/CP)
When THESA is employed, this process is shortened because assembly and driving
tests are omitted.
When using rapid prototyping processes, the process can be further shortened insofar as the mold making is substituted by a rapid prototyping model that is cast
directly in a precision casting process.
The decisively shorter development process is achieved by being able to test the
sintered polyamide rapid prototyping component directly by means of THESA,
thereby eliminating the necessity of the entire casting process. Figure 4.54 shows
an exemplary thermographic image with a defined stress and, in comparison, the
same situation with a molded aluminum wheel rim. The conformities are excellent,
as documented by the totals of the main tensions given in the example over the
radius at the center of the component (Fig. 4.55).
4.3 Operational Aspects in the Use of Prototypes
Figure 4.54 THESA, thermographic reproduction of a rapid prototyping component (poly­
amide) (left) and of an aluminum series part (right) (Source: Schwarz/CP)
Sum of
Normal Tensions
0
Radius
Plastic Rim (SLS)
Aluminum Rim
Figure 4.55 THESA, total of the main tensions over the radius in the center of the component
(Source: Schwarz/CP)
When THESA is used for sintered plastic components generated by rapid prototyping, the time needed for the iteration loop is reduced to 20 % of the time previously
needed. The greatest single effect is the reduction of production time from 18 days
for a cast component to three days for a polyamide component. By applying this
351
3524 Rapid Prototyping
modified THESA process, the entire development process can be reduced dramatically, although not down to 20 % of the previous time because the final test
for a safety component still needs to be run with a component made of the original material.
„„4.4 Outlook
For solid images and concept models, the trend is toward cheap and easy-to-use
personal printers that can be used at home or in the office. The production of models requires less or no data preparation and also no or less manual postprocessing.
The price limit for the mass production is today at around 5,000 € (just over
$5,000), and for self-made systems and kits the price is between 1,000 € and
4,000 €. The ProJet 1000/1500, which was presented as V-Flash in 2007, shows
the way.
The development of machines for the production of functional prototypes goes in
another direction. The coupling of machines and materials today allows the given
assignment of model requirements to the additive processes. In the future, development will concentrate on the materials, and from this there will be a bigger material range for every machine available. The models and prototypes will become
more and more powerful, but the choice of a process is getting complicated. From
today’s optimization of two groups of process parameters, the model definition and
the additive process, three groups of parameters will grow: the process, the model
definition, and the material.
The development of machines will lead to a reduction of the necessary manual
postprocessing and partially reduce costly finishing. Models and prototypes will
then be easier to reproduce, and also be available quicker. Office-usable processes
that produce hazardous waste and require the use of solvents, alkalis, and the like
will be less accepted.
4246 Direct Manufacturing: Rapid Manufacturing
frequency identification (RFID) should be checked for their utility. The documentation must permit the production of a replacement part at any time.
6.3.3.6 Logistics
Logistically, the additive manufacturing process is therefore a “manufacturing on
demand,” or a just-in-time manufacturing of single parts. The difference from the
logistics of current big series is not irrelevant, because due to the single part character, the parts are not delivered in containers or other bulk packaging for further
assembly, but must be placed as individual items in the usage site.
Variant production by the automobile manufacturers is already an indication of
this integrated logistics and production engineering task. In the Audi A6 (built in
2005), for example, 18,000 different door panels can be installed. A journal on
auto­mobile production headlines it accordingly: “Insanity with method” [Automobil Produktion, 05]. With these numbers, it is still a matter of parts that are in series, albeit small, and produced with current production methods.
Therefore, series products are combined with other series products to form individualized mass products with a unique image. But all part products relied on for
individualization are part of series and logistically can be treated as anonymous
series products charge-wise.
Additive manufactured individualized products are unique in manufacturing
­technology as well. In the future, “single part-uniques” are completed with other
“­single part-uniques” to complete “product-uniques.” Logistically, consequently, all
elements of the whole supply chain are to be treated as individual parts.
Logistically, the task also is to implement a suitable merger between the product
with all of its parts and all necessary accessories, also individualized, such as manual, warranty certificate, and packing material. Finally, everything must be archived so that the individual access is ensured at all times and over a long period
of time.
„„6.4 Implementation of Rapid Manufacturing
In the application of the methods of additive manufacturing, different scenes are
possible. AM machines are integrated as elements of a mostly nonadditive multicomponent fabricator in the manufacture process as well as decentralized for
­complete additive manufacturing. They are used in industry or privately as personal printers. Depending on the application case, different machine concepts
will emerge. The developments conceivable today are introduced next with examples. The transition from current additive manufacturing in the concept of rapid
6.4 Implementation of Rapid Manufacturing
prototyping to rapid manufacturing takes place smoothly. It had already begun
some time ago.
Classifications are not reflected accurately in these following examples because, in
practice, mixed forms tend to occur.
6.4.1 Additive Manufacturing Machines as Elements of a
­Process Chain
In industry, rapid manufacturing that has already been introduced by additive
methods was integrated into a production network with nonadditive methods.
Parts are manufactured that are additionally machined, finished, and assembled
with other products in the course of the production chain. An example of a simple
combined process is the production of a titanium structure for aviation (Titanium
6Al-4V); see Fig. 6.21. The structure is additively manufactured on a milled plate,
heat treated, machined to size, separated from the stabilizing base plate by machining, and measured. The structures have characteristic dimensions up to 2500
mm. The additive method consists of an adapted LENS process (see Section 3.3.2)
and machine finishing. It is marked by a high percentage of manual operations.
Figure 6.21 Combined additive and conventional manufacturing process for aviation
­components made of titanium (Source: Aeromet)
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4266 Direct Manufacturing: Rapid Manufacturing
In the field of plastic molded parts, a combined conventional and additive manufacturing is also possible if plastic injection-molding machines do large quantities,
while parallel to that, the additive machines provide the single parts.
For that, the additive machines must be free of manual work parts (according to
Section 6.3.3, “Future Efforts in Additive Series Production”) and be integrated
into production lines.
6.4.2 Additive Machines for Complete Production of Products
Additive manufacturing methods have the potential to directly manufacture not
only components, like plastic moldings, but also complex products (see Section 6.2,
“Potential for Additive Manufacturing End Products”). Such approaches represent
a paradigm shift from today’s multipart single part and assembly-oriented production technology to an additive one-step manufacturing of complex products.
6.4.2.1 Industrial Complete Production
In the form of complete manufacturing machines, fabricators will enable the manufacturing of selected parts or complete products. One example is the 3D printing
machine of Therics Theriform that can produce up to 40,000 pills per hour with
complex inner structures and distributed active components. The pills leave the
machine already packed (see Fig. 6.22).
Figure 6.22 TheriForm 3100: manufacturing of pills by 3D printing machine (left),
pill outer view and in section (right) (Source: Therics)
Because producing additive manufacturing machines do not have to be integrated
into production lines, but constitute the lines themselves, and because any spatial
separation of design and production is possible, their operation and installation can be decentralized. A central design with a decentralized manufacturing
can be realized, and vice versa, as well as all conceivable combinations. Especially
6.4 Implementation of Rapid Manufacturing
attractive would be the equipping of customer service centers for the direct production of the required accessories and spare parts or the adaptation of hull products with country specific, locally additive manufactured attachments.
The industrial fabricators for those applications must include all of the properties just discussed in future AM machines and in particular, to ensure a high productivity.
Examples of products are a one-piece additive manufactured cable clamp with two
integrated hinges and cable guides with integrated clamps (Fig. 6.8) or the gripper
in Fig. 6.5.
The nozzle plate produced by microTec (Fig. 6.23) is an example of the micromanufacturing of components. As part of a catheter, it drives the turbine wheel of the
mill. Its diameter is 4 mm, and the outlet cross section of each nozzle is 20 µm. The
plate consists of biocompatible material. It is an example of microparts that cannot
or can only with much greater effort be manufactured with conventional methods.
Figure 6.23 Nozzle plate (Source: microTec)
An example of an integrated product that, from the point of view of the manufacturer of mobile phones, represents one component, is a tapered helical mobile antenna manufactured with the M3D Technology of Optomec. See Fig. 6.24.
427
4286 Direct Manufacturing: Rapid Manufacturing
Figure 6.24 Mobile antenna, aerosol printing (Source: Optomec)
6.4.2.2 Individual Complete Production (Personal Fabrication)
With complete and in one step automated additive manufacturing machines,
non-manufacturing technicians can also produce products. This is possible through
personal printers or fabbers (Section 3.5.2). They are available as complete machines
with good part properties (FDM Mojo, Polymerisation ProJet 1000/1500) or as fabbers with reduced component quality, but at very affordable prices, either as complete machines or as an assembly kit. The bottom price for a DIY fabber of the type
Prusa Mendel is today (2013) at about 600 € (about $ 675).
In combination with a personal computer, those kinds of fabbers or personal 3D
printers represent complete production systems for individual decentralized production. The implementation, especially in a private setting, has already begun.
The data come from a personal 3D design that can be created by anyone with programs like Google SketchUp or as a complete data set from Internet portals like 3D
Warehouse or Shapeways.
With this, the over 10-year-old scenario is becoming realistic in which children
design system construction kits and other toys on the computer on their own and
directly manufacture them. The 3D printing blogs provide assistance and promote
the exchange of experiences. Self-made spare and additional parts are therefore no
longer ideal. The step from cybercommunication to cyberproduction has been taken.
The productivity for these applications mostly plays a subordinate role, and manual work parts are accepted.
An example of personal fabrication is the model of a camshaft wheel (Fig. 6.25). It
was manufactured with the (up to 2006) easiest and cheapest machine, the LD3
Printer (Section 3.4.10). It is easy to imagine that in this way, system assembly
kits, components of model toys, or spare parts can also be manufactured.
6.5 Application Fields
Figure 6.25 Camshaft wheel as example for system toys (Source: Solidimension)
„„6.5 Application Fields
During the discussion of additive manufacturing machines, it has already become
clear that development is running in two directions. One of them leads to universal
machines, the other one to specialized applications, also in the sense of branch
solutions. Both trends will grow further in future.
More specifically, for the so-called universal machines there are also two lines of
development. One leads to simple office-suitable or also privately usable machines
that are summarily described as personal 3D printers.
The other one leads to complex additive manufacturing machines that require a
manufacturing infrastructure and are suitable for developers, for in-house or independent service providers, or for research laboratories. With them, depending on
the application, end products (production 3D printer) or also prototypes (professional 3D printer) can be manufactured.
The specialized machines aim at the processing of special, often also branch-specific materials or material families. But they contain also more often packaged
solutions, consisting of the additive machine, a branch-specific software solution,
and materials matched to the process. Both the total packages as well as the pure
service are offered. In each case only finished products or their components are
manufactured.
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4306 Direct Manufacturing: Rapid Manufacturing
Therefore, from the point of view of additive manufacturing technology, application
fields have been developed that it can be usefully structured by materials or by
branch. Of course the areas have strong interactions with each other.
6.5.1 Application Fields for Materials
This chapter gives an overview of selected, particularly heavily developed areas of
application. It does not claim to be complete.
The processes and the mechanical-technological properties of the materials will
not be discussed in detail. These are described in Chapter 3 and compiled in Appendix A3.1/A3.12.
6.5.1.1 Metallic Materials and Alloys
The development of metallic materials is oriented preferably in niches that contain
attractive boundary conditions for additive manufacturing. Niches with respect to
the application are flow-conducting, thermally loaded parts, such as the turbine
housing of a turbocharger in Fig. 6.26.
Figure 6.26 Casing of the turbine of an exhaust turbocharger. Selective laser sintering, after
the building process (to the left) and after finishing (right) (Source: 3D-Systems)
6.5 Application Fields
Industry niches include aerospace and medical technology. The applications are
characterized by small numbers or single parts. These industries are used to materials that are specially prepared and sensitively monitored, and to extensive testing of each part. Also, one is more willing to tolerate an appropriate price level for
this effort.
Titanium and CoCr alloys are the keys to these branches. All suppliers of metal
processes (Sections 3.2 and 3.3) have multiple relevant approved materials. The
parts are all end products.
The niches also include the tooling, although altogether it is a very large industry.
The basic requirement to offer tool steels was first fulfilled a few years ago. The
tendency, compared to nonadditive processed steels, to higher strength and lower
elasticities is increasingly overcome. The range is still small and often includes
only a few materials per supplier, but it is growing very dynamically.
6.5.1.2 High-Performance Ceramics
Unnoticed by many and hidden by the efforts in the processing of metallic materials, applications have been developed in ceramic materials for all additive process
families [Gebhardt, 07]. Used are 3D printing and extrusion processes, polymerization and layer laminate processes with subsequent sintering processes, and also
direct applications of the additive sintering technique. Figure 6.27 shows a filter
element made with the Ceraprint 3D printing process, which has been modified by
Specific Surface based on the MIT license.
Figure  6.27 Ceramic filter element
(Source: Specific Surface)
Direct sintering in the high-temperature chamber was developed by Phenix and
implemented industrially. The process is described in Section 3.2.12. Figure 6.28
shows a ceramic heat exchanger with an intricate internal structure.
431
4326 Direct Manufacturing: Rapid Manufacturing
Figure  6.28 Ceramic heat exchanger
(Source: Phenix)
The range of ceramic materials covers almost the entire spectrum: shapes and
parts made of Al2O3, SiO2, ZrO2, and SiC, fully sintered Si3N4, and so-called graded
materials, such as zirconia-reinforced aluminum (ZTA) formed by coating ZrO2 on
an Al2O3 layer or a corresponding substrate.
Monolithic ceramics are manufactured, but flowed mainly through or with high
temperatures impinged structures. Defined macroporosities are the basis for implants of resorbable bioceramics. Microporosities are used in reactors, but especially in tribological systems.
6.5.1.3 Plastics
Many critics focus primarily on devaluing additive processable plastics when parts
do not have properties equal to those of nonadditive plastic parts, especially when
processed in a thermoplastic injection mold. This is mainly a question of the d
­ esign
(compare Section 6.3.3.4, “Design”), but consequently this criticism causes intensive work on the improvement of existing materials systems, and the qualification
of new ones.
Certain specific additively processed materials, such as polyamides, can come
quite close to the properties of their nonadditively processed counterparts, but
overall this is still some way away from a technically important range, especially
for the high-performance materials (see Fig. 6.18). The qualification of PEEK has
already been achieved, and the important PA 6 is scheduled to launch.
An important application of plastics is in the casings (shells) for in-ear hearing
aids. If the relevant data were available, hearing aid shells could have been additive manufactured since 1991. In addition to the development of appropriate software packages for the design of the shells, the development of materials provided
the breakthrough that means that worldwide an estimated 85% of all hearing aid
shells are manufactured with (different) additive processes today (see Section
6.5.2.3, “Medical Equipment and Aids, Medical Technology”). The breakthrough
6.5 Application Fields
came with the development of a material that can directly and permanently be
worn in the ear (see the next Section 6.5.1.4, “New Materials”).
Alternative plastic materials are pigmented polyamide for the sintering process
and colored resins based on (meth)acrylate for polymerization processes.
6.5.1.4 New Materials
According to the previous section, the development of hearing aid shells required
new materials. Radiation-curable resins from the SLA technology are not usually
biocompatible. The reasons are often the use of a combination of radical and cationic curing (hybrid system), and the selection of highly reactive unsaturated epoxy
compounds. Therefore, new biocompatible materials have been developed for the
otoplastics that are permanently in contact with the patient. By means of an anaerobic inhibitor, 2,2,6,6-tetramethylpiperidin-1-yloxy (TEMPO, free radical), the resins were stabilized, and the photosensitivity was adjusted so that a low radiation
energy results in the greatest possible depth of cure with a high degree of poly­
merization, good green strength, and sufficient stability (material: Fototec, [Klare,
05]). The final products obtained by complete curing not only have good mechanical characteristics, but also exhibit excellent biocompatibility, are hard-elastic, and
show a very low water absorption. The material is opaque or transparent.
In microtechnology, the material is often the deciding factor for a successful application, and frequently this material must be developed or modified. In this context,
the use of a service provider is often the better choice. This is the business model
of the company microTec (Section 3.1.6), which also undertakes individual material development.
New materials created through the composition of different layers of, among others, plastic, metal, ceramic, or even living cells, are produced by the M3D method
of Optomec (Section 3.6.6).
6.5.2 Application Fields by Industry
This section provides an overview of selected applications that have been strongly
developed. It does not claim to be complete.
The processes and the mechanical-technological properties of the materials will
not be discussed in detail. These are described in Chapter 3 and listed in the appendix.
6.5.2.1 Tooling
In addition to the basic requirement to offer tool steels that match the properties
of nonadditive processed materials, the additive systems must be integrated in
433
4346 Direct Manufacturing: Rapid Manufacturing
particular into the production flow in the tooling. Some systems are tailored to the
tooling in this sense. They build up for example on a system holder or integrate
pallet or clamping systems, which can be aligned with little effort for the subsequent steps in nonadditive machines. Examples were discussed in Section 5.4.3.
In tooling, it is essential to optimally match additive and nonadditive elements
­together. One example is the ecoMold project [Hennings, 04] that touches upon the
DMLS processes (Section 3.2.4) but, in principle, is possible to implement with
each sintered metal or fusion process. The starting point is a modularization in the
sense of dividing additive and nonadditive manufacturable elements.
The nonadditive finishing work is enabled by clamping elements. Figure 6.29
shows an element after additive processing, a compilation of all of the elements
and the clamping plate and the fully assembled mold half.
Figure 6.29 Ecomold: additive construction process (above), additive and nonadditive
­manufactured tool components (bottom left), and assembled tool half (bottom right)
(Source: IFAM)
The application tooling is particularly discernible by design enhancements that
are only additively implementable. Of special significance is conformal cooling. It
was presented and discussed in Chapter 5.
Index
Symbol
2½D processes 23
2D CAD sketches 32
3D CAD 28
3D-CSP 122, 124
3D Keltool 119
3D-Micromac 166
3D printers 16, 70, 88, 248
3D printing 3, 69, 384
3D printing method 402
3D printing system 263
3D processes 91
3D sintering machine 156
3D Systems Inc. 110, 137, 143, 153, 247
3Z EDU 244
3Z LAB 244
3Z Pro 244
3Z Studio 244
5600 125
A
ABS 118, 242
accommodation expenses 466
accura amethyst 118
accura bluestone 118
accurate clear epoxy solids 116
ACES injection molding process 116,
119, 379
acrylates 56, 454
acrylic glass 266
active customization 404
active recoater 115, 121
Actua 247
additive layer manufacturing 3, 12, 21,
25
additive manufacturing software 26
Adrian Schoormans 339
advanced direct manufacturing (ADM) 154
aerodynamic focusing 268
aerosol printing process 71, 83, 89, 90,
207, 267
aerosols 267
AIM 119, 379
air ejectors 357
air separation unit 159
Alisa Minyukova 340
AlSiMg10 175
AluMide 172
aluminum 274
aluminum silicate sand 175
amorphous materials 148
amorphous plastics 58
amorphous polystyrene 172
analysis 346
anatomic facsimile models 333, 335
Arcam 200 196
Arcam A2 192
Arcam AB 192
Arcam ASTM F75 CoCr 197
Arcam H13 196
Arcam Q10 192
architecture 341
ASCII data 34
Association of Industrial Designers and
Stylists (VDID) 302
582
Index
automatic layer methods 216
Autostrade 141
B
ballistic particle manufacturing 449
ballistic process 91
bare dies 124
base (platform) 148
basic solids 30
beam diameter 149
beam interference solidification 73
beam melting 57, 146
beam-width compensation 99
benchmark parts 285
beryllium alloys (AlBeMet) 197
BFF file 114
biocompatibility 454, 455
biometric 3D data 405
BIOplotter 128
blind planning times 306
BlueCast 246
body scanning 33
BOS 156
boundary curves (borders) 99
boundary error 37
Breakaway Support System (BASS) 236
breakout station 156
bridge tooling 10, 354
bubble-jet nozzles 79
building law 452
Buildstation 113, 114
C
C4W 201
CAD to Metal 193
CarbonMide 172
CASM (Computer Assisted Satellite
Manufacturing) 275
CastForm 159
CastForm PS 161
cast resin tools 371
cationic polymerization 47
ceiling temperature 48
ceramic 390
–– ceramic materials 431, 480
–– ceramic models 201
–– sintering machines 150
Ceramics 5.2 175
Ceraprint 431
Charlyrobot 225
chemical law 452
chip size packaging 122, 124
cleaning sintering models 150
CLI 38, 167
–– data format 40
–– file 40
CNC-Schichtfräs-Zentrum LMC 225
CO2 laser 77
Co alloys 212
coaxial nozzle 205
cobalt-chrome (CoCr) steel 179, 201
Cobalt Chrome MP1 174
Cobalt Chrome SP2 174
color, physical property 407
common layer interface 167
components 319, 325
computer-aided modeling devices
­(CAMOD) 127
computer sculptures 337
computer tomography 33
Concept Laser GmbH 185
concept model 304, 352
concept modeler 137
conditioning 149
conformal cooling 356, 434
conglutination of granules 83
construction materials 412
construction platform 115
consumer goods 463
continuous coaxial nozzle 205
continuously colored parts 249
contour border 114
contoured 21
contour-oriented interface 38
controlled metal buildup (CMB) 270
coordinate measuring arm 287
coordinate-measuring device 33
 Index
corner model 29
costs of additive manufacturing
­processes 461
Course4 Technology 119
craniofacial surgery 405
craniosynostosis 335, 336
critical energy 54
critical success factors 459, 496
critical surface energy 48
cross-linking 56
crystalline materials 148
crystalline plastic 58
Cubic Technologies Inc. 219
cure depth 49, 50, 52, 53
curl 149, 159, 220
customer service 471
customization 403
cutting from foils 83
cutting in the CAD 33
cutting plotter 230
cutting speed 66
cyberproduction 449
cyclic build style 114
Cyclone 377
–– powder feeders 207
D
degree of polymerization 48
demasking fluid 229
densification furnace 254, 256
dental market 254
dental technology 436
dentistry 174
deposition welding 65
depowdering unit 252
description error 37
design for additive manufacturing 422
design for rapid manufacturing 422
design models 342
desktop concept modeler 229
desktop manufacturing 12
diameter of the powder 90
digital light processing 126
digital manufacturing 9
digital product model 29
Digital Wax Systems 141
DigSmugg 438
Dimension 234
Dimension 1200es 233
Dimension Elite 233
DIN 8580 84
DirectCast 171
direct casting 382
direct contour generation 39
direct core and mold-making machine 253, 257
Direct Core and Mold Making System 382
direct laser forming 191, 389
direct manufacturing (DM) 9, 62, 395
direct metal 385
–– deposition (DMD) 191, 209, 392
–– fabricator 211
–– laser sintering 169
–– printer 255
–– printing 253, 385
DirectMetal 173
DirectMetal 20 173
direct method 354
DirectPart 174
DirectPart process 169
direct pattern 381
direct rapid tooling 10
direct shell production casting (DSPC) 259, 260
DirectSteel 173
DirectSteel H20 173
direct tooling 10, 62, 354, 379, 385
DirectTool process 169, 387
discrete coaxial nozzles 205
disorientation 37
DLP 126
DLP module 145
DMD 105 209
DMLS 169, 175, 387, 434
double triangle patches 38
downskin 119
drainage opening 55
drop-on-demand (DOD) 244
583
584
Index
DSPC-1 259
DTM Corporation 153
dual spot 115
DuraForm 159
DuraForm AF 162
Duraform EX 162
DuraForm Flex 161
DuraForm FR 162
DuraForm GF 160
DuraForm PA 160
DuraForm V63 160
DWS S.r.l 140
dynamic voxel thickness 131
E
EBM 192, 390
EBM Control software 193
ecoMold project 434
E-darts series 142
edge model 30
EDM 389
electron beam melting 192, 390
electron beam sintering 390
electron beam source 194
Electro Optical Systems GmbH (EOS) 165
ELI 174
e-manufacturing 9
emission-control law 452
ENDFACET 34
energy costs 463
engineering materials 88
Enhanced Resolution Module 131
environmental protection 451
EOS 165
EOSINT M 165, 169
EOSINT P 165, 167
EOSINT S 165, 171
EOS RP Tools 167
epoxy resins 56, 118
E-Shell 100 131
EXACT style 118
excess energy 54
excimer laser 124
ExOne 253
external producer 472
extra-low interstitial 174
extruder 83
extrusion materials 455
extrusion processes 68, 90, 232
F
fab-at-home 449
fabbers 16, 449
fabricators 395
Fabrisonic 272
FACET 34
FAST architecture 118
Fast Sculp 215, 377, 401
fault tracking system 198
FDA 124
FDM machines 233
fiber laser 77, 89
filled resin (nanocomposite) 118
film transfer imaging (FTI) 143
Fine Point Method 101
flame-retardant 172
Flash Curing System 145
flat-field lens 75
fleece 150, 252
FLM 83, 232
Fockele & Schwarze (F&S) Stereolithographietechnik GmbH 121, 176
follow-up processes 289, 354
Ford Sprayform 374
formative manufacturing technology 1
Formiga 165
Fortus 233
free-form fabrication 193
front-end software 26, 38, 113
front loading 295
FS-Realizer 121
F&S Stereolithography GmbH 121, 176
F-theta lens 75
FullCure-705 135
functional prototype/model 302–304
functional prototyping 7
fused deposition modeling (FDM) 233
 Index
fused layer modeling (FLM) 66, 232
F. Zimmermann GmbH 225
G
galvo scanner 75, 98
gel point 48
generation from the gas phase 83
generation from the solid phase 45, 57
Generis 254
Genisys 234
geometric prototype 305
Georg Glückman 337
graded materials 70, 449
Graphtec XD 700 229
green phase 54
green product 56
gussets 101
H
hatch 114
heat conduction 148
Helisys 219
holographic interference solidification 73
hot isostatic pressing (HIP) 174
Hot Plot 198
HPGL format 32, 33, 39
HS Celerity BDS (beam delivery
­system) 155
hybrid models 30, 31, 342
I
IMLS 383
impact processes 76
implant 405, 432
implant alloys 174
Inconel 620 197
Inconel 625 197, 209
Inconel 718 197
incorrect orientation 37
indirect methods 354, 363
indirect rapid prototyping 10, 293
indirect tooling 10
individualization (customization) 403
individualization of mass products 494
InduraBase 246
InduraCast 246
InduraFill 246
inerting the machine 147, 159
infiltration 255
infrared light 197
initial reaction 46
initial sample test report 287
inkjet 250
inkjet print head 245
Insight 235
intelligent powder cartridges 156
internal hollow 63
investment casting 118
–– components 119, 377
–– wax (ICW 06) 243
investments (costs) 464
invisible supports 193
InVision Finisher 140
InVision print client 137
IPC 156
island (support) 101
isochromatics 346
isopropanol 56
J
JAR 172
JCAD 141
JewelCAD 437
jewelers 255
jewelry industry 437
jewelry market 254
K
kinematics 328
Kinergy Precision Engineering,
Co. Ltd., 223
KIRA Corporation 224
KIRA Europe GmbH 224
585
586
Index
knife 83
Kodak angle 148
L
lab on a chip 402
lamella tools 393
laminated metal prototyping 230
laminated metal tooling 393
laminating and ultrasonic welding 272
lamp-mask method 97, 126
laser 83
laser chemical vapor deposition 72
laser cladding 203
laser coating 203
laser cusing 185
LaserCUSING 389
laser-engineered net shaping (LENS) 206, 391
LaserForm 159
laser generating 203, 391
laser melting 176, 180, 182, 388
laser scanner stereolithography 97
laser scanning process 45, 100
laser sintering 200, 390
–– principle 147
laser stereolithography 97, 102
Layer file 114
layer-generating element 83
layering process 22
layer laminate manufacturing 65, 89,
90, 213
layer milling 89
–– processes 216
layer processes 87
layer thickness 22, 52, 115
LD 3D printer 229
LENS 450 206
LENS 850-R 206
LENS MR-7 206
Lightyear 113
line-width compensation 99
liquid phase sintering 61
LLM 83
LOM 1015plus 218, 221
LOM 2030H 218, 221
LOMComposite 222
LOMPaper 222
LOMPlastic 222
lot sizes 467
M
M290 165
MAGICS RP 154
make or buy 472
manual layer laminate manufacturing 216
manual sketches 32
manufacturing on demand 424
Maraging Steel MS1 174
mask process 45, 56, 78
mask tools 372
material consumption 468
material costs 462
Materialise Magics 167
Materialize 113
mathematical rules 336
medical models 332
medical techniques 124
medical treatment 332
medicine 331
Meiko 141
melting 83, 146
–– and solidification 83
–– cores 313
MEMS 402
mesocomponents 401
metal and molding sand printer 253
metal blades tools 393
metal foil LOM 231
metal foil tools 231
metal spraying process 370
microblasting 175
microcomponents 475
microelectromechanical systems 402
microelectronic components 207
microlaser sintering 166
microsintering 475, 476
microstereolithography 122, 475
 Index
microstructure 72
–– of ceramic powder 480
–– of metal powder 477
microTec 433
milling tool 83
Millit 216
mirror triangle 327
MJM 137, 247
MK Technology 377
mock-up 291
model classes 302
model construction time 470
model definitions 302
Model Maker 245
model materials 88
model of a skull 410
models 291, 302
ModelWorks 245
Mojo 3D Printer 233
molding processes 354
molding sands 171
monomer 46, 47
motivation 300
moving element 74
multicomponent metal-metal powder 61
multicomponent metal-polymer powder 60
multijet modeling 137, 247
multijet nozzles 205
multilayer coating 203
N
naked edges 38
nanocomposite 118
Nano Cure RC25 131
nanotechnology 122
neutral interfaces 28
NextEngine 141
Nickel Alloy IN625 174
Nickel Alloy IN718 175
nickel-based alloys 212
Ni-Co-Cr-Al 212
nitrogen 159
noncontact processes 76
nozzle 83
nozzle-lamp process 46
nylon casting 369
O
Objet Geometries Ltd 132
Objet Polyjet 108
Objet Studio software 133
off-axis nozzles 205
office printer 16, 229
offline thermal station 156
offload cart 112
one-layer operation 222
optical penetration depth 49
OptoForm 146
Optomec Inc. 206, 267
Optomec M3D 267
OTS 156
outer layer 114
overcure 115
overlap 37
P
PA 11 59
PA 12 59
PA 2200 172
PA 3200 GF 172
paraboloid of revolution 98
Parts Now 260
paste polymerization 146, 384
pattern 313
PatternMaster 245
PC 118
penetration depth 53
Perfactor4 Standard, Perfactory Mini,
Perfactory Desktop, Ultra 126
Perfactory R5 130
Perfactory Y8 130
personal 3D printers 16
personal fabrication 428
personal fabricator (PF) 409, 449
Personal Factory 127
587
588
Index
personalization (customization) 403
personnel expenses 466
Phenix Systems 200, 431
phenolic resin 175
photoelastic stress analysis 346, 348
photopolymer 145
photopolymerization 45, 83
piezo nozzle 80
planarizer 138
planning targets 288
plastic materials 148
plastic powder 58
plastics 67
plotter 83
plotter unit 90, 280
PLY 32, 250
PLY and VRML formats 41
PMMA (polymethyl methacrylate) 266
point clouds 33
polyamide 59, 148, 454
polycarbonate 118, 148, 151, 243, 454
polycondensation 171
polygon file format 41
PolyJet 132
polyline instructions 39
polymerization 45, 47, 89–91, 97, 108,
454
polymerization rate 48
polymer printing 83, 132
polymer printing process 55, 97
polyphenylsulfone (PPSPH) 67, 243
polypropylene (PP) 131
polystyrene 148, 151, 454
polysulfide 67
polyurethane casting 372
POM 5050 Direct Metal Fabricator 209
positioning of the component 149
post-cross-linking 110
postcuring oven 56, 105
postprocessing 27, 281
potentials of additive manufacturing 276
powder-binder processes 69
powder cake 150
powder handling 154
precipitation from the gaseous phase 45
precision-casting process 149
Precision Optical Manufacturing 210
preprocessing 280
PrimeCast 101 172
PrimePart 172
printing head 83
production 3D printers 16
professional 3D printers 16
projections process 46
ProJet 248
Prometal 253, 254
propagation reaction 46
property-protection law 452
ProtoBuild 246
ProtoSupport 246
prototypers 335
prototypes 348
prototype tooling 354, 379
prototype tools 379
PS 2500 172
pulse-pause relationship 55
PXL 200
PXM 200
PXS 200
PXS Dental 200
Q
qualities of surfaces 90
Quartz 4.2 175
Quartz 5.7 175
quartz sand 175
quick-building module 164
Quick Cast 116, 118, 215, 377, 401
QuickSlice 235
R
rapid change module 155
rapid manufacturing 9, 11, 123, 151, 395
rapid micro product development 123
rapid prototyping master pattern 313
rapid prototyping (RP) 7, 11, 291
 Index
Rapid Prototyping Systems (RPS) 223
RapidSteel 162
RapidTool 162
rapid tooling 10, 353
raster process 78, 155, 207
rate of polymerization 53
RCM 156, 159
RDM 112
reaction injection molding 372
Realizer GmbH 176
Realizer SLM50 176
Realizer SLM100 176
Realizer SLM250 176
recoating 98
–– parameters 113
–– system 170
recycling station 164
redundancy avoidance 31
Renishaw Inc. 182
repair costs 463
resin bath 98
resin delivery modules 112
resin parameters 114
resin shrinks 48
resin tanks 112
reverse engineering 33
RMPD (Rapid Micro Product
­Development) 122
RMPD mask 124
RMPD multimat 123
RMPD stick2 122, 123
Röders GmbH & Co. 270
roller 155
roughness measurements 285
row width (RW) 235
rp2i 225
RSP 374
S
S750 165
safety 451
samples 291
sand cores 175, 254
sand mixer 258
sand molds 254
scanner 83
scanner unit 280
scanning optics 75
Scialex Corp. Ltd. 133
Scitex Corporation 133
sculptor 339
sculpture 340
secrecy guarantee 472
selective adhesive and hot press
­process (SAHP) 224
selective laser sintering 383
selective mask sintering (SMS) 192,
197, 381
selective sintering 146
semipolymerizing 346
shadowing 280
shape welding 203
Shaw methods 374
sheath core 174, 215
sheet metal processing 388
shell cracking 119, 149
show-and-tell models 7, 302
SHR 134
shrink 149
shrinking (scaling) 70
single-component metal powder 385
–– and ceramics 61
–– methods 386
single head replacement 134
single-layer coating 203
single-stage 56
sintering 57, 146
–– and melting processes 152
–– of plastic materials 58
–– processes 57, 87, 89–91
sinter materials 454
Sinterstation 153
SinterStation Pro 164
Skin and Core 167, 377
SLA-250 102
SLC formulation 32, 38, 39
slice on the fly 164
slicing 33
SLM Solutions GmbH 180
589
590
Index
Smart Sweep 115
S-Max 257
SoliCast process 125
Solid Concepts 113
solid foil polymerization 73
solid free-form manufacturing 12
Solidica Inc. 272
solidification from the gas phase 71
solid images 352
solid imaging 305
–– or concept modeling 7
Solidimension 229
solid object printer 137
solids 30
Solidscape Inc. 244
Soligen Technologies Inc. 259
solvent 455
SonicLayer 272
spare parts on demand 408
SPARX AB 198
spatial trusses 102
Speed Part 192
Speed Part partmaker powder 199
Speed Part RP3 197
Speed Part toolmaker powder 199
S-Print 257
sPro 154, 155
sPro60 153
sPro125 153
sPro140 153
sPro230 153
stainless steel 17-4 174
stainless steels 179
stair-step effect 22, 23
STAR-Weave technique 100
state of technology 452
steel 316S 209
stereography 45, 97
stereolithography 45, 47, 54, 56, 87, 97,
346
–– appartus (SLA) 110
–– interface 34
STEREOS DESKTOP/300/400/600/
MAX 600 120
STEREOS stereolithography 120
sterilization 455
STL 32, 34
STL format 26, 34
STO-Serie Fräsmaschinen 225
Stratasys Inc. 233
Stratasys System Language 235
Stratoconcept 225
Stratoconception 225
Stratoconcept STE-Series 225
Stratoconcept VR Software 225
stress analysis 345
subtractive manufacturing technology 1
super alloys 212
support generator 113
supporting material 55
support structures 55, 56, 89, 98, 100,
101, 114, 147
Support Works 235
surface determining models 30
surface energy 49–51
surface quality 282
surface sealings 151
swap bodies 119
systematics of manufacturing
­technologies 1
system costs of AM machines 465
T
Tango 135
termination reaction 46
texturing 42
Therics Theriform 426
thermal polymerization 73
thermoelastic stress analysis 345, 347
thermoforming 380
ThermoJet 137, 247
thermoplastics 149
THESA 350
thin-layer architecture 118
three-dimensional printing (3DP) 248,
260
Ti6Al4V 174, 209
Ti6Al4V ELI 196
 Index
Ti6Al4V (Grade 5) 196
titanium 179
titanium Ti64 174
tool-less fabrication 9
tool steel 179, 212
track width 52
translucent 55
transparency 332
transparent 55
triangle patches 34
triangulated surface 35
triangulation 33
TrumaForm DMD 505 209
TrumaForm LF130 191
TrumaForm LF250 191
TRUMPF Laser GmbH & Co. KG 191,
209
two-photon process 45
U
Ultem 9085 243
ultrasonic welding 65
unloading station 258
uPrint 233
user parts 286
UV light sources 45
V
vacuum deep drawing 380
Vanquish 127
VDID 302
Vector Bloom Elimination 163
vector process 77
VeroDent 135
V-Flash 144
Viper Pro 112
virtual modeling 339
virtual product model 26
virtual reality 345
–– modeling language 41
Voxeljet Technology GmbH 263
voxel structure 99
VRML 32, 43
VRML(II) 250
VX 800 263
W
waste-material law 452
water law 452
Water Works (WW) 236
waxes 67
wax injection tools 275
wax printers 244
Weihbrecht 231
working curve 50
Z
Z Corp 249
z correction 115
Zephyr recoating system 115
ZIPPY I 223
ZIPPY II 223
ZPrint 250
591
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