Additive Manufacturing of Metals (eBook)

John O. Milewski received his B.S. in Computer Engineering from the University of New Mexico and his M.S. in Electrical Engineering from Vanderbilt University. He began his technical career with five years’ metal fabrication experience ranging from heavy industry production as an ASME code welder to light manufacturing and applied research. He spent 32 years at Los Alamos National Laboratory, in positions including Welding Technologist, Engineer, Team Leader, Experimental Component Fabrication Program Manager, and Group Leader for Manufacturing Capability. He is currently retired from the Lab, writing and consulting as APEX3D LLC regarding the new and exciting applications of AM technology. His technical expertise includes arc systems electron beam, laser welding, robotics, sensing and controls, and the joining of less common metals. His work experience also includes CAD/CAM/CNC model based engineering, process modeling, and simulation with validation methods to include residual stress measurement. In addition, he served 2 years in the late 1980s as Vice President of Synthemet Corporation, an entrepreneurial high tech start-up, with the goal of development and commercialization of 3D additive manufacturing of metals.  He is author and co-author of numerous publications related to high energy beam processing and process modeling. His awards include an R&D 100 Award for Directed Light Fabrication, Fellow of the American Welding Society (AWS) and the AWS Robert L. Peaslee Award. He is inventor or co-inventor for a number of patents related to laser welding and additive manufacturing.  He has had extensive formal collaborations with universities and sponsored students resulting in refereed publication and patenting. His professional society involvement included Chairman, Co-Chairman, and advisor of AWS committees related to High Energy Beam, Electron Beam, and Laser Beam Welding. In addition, he currently serves as an advisor to the AWS D20 Additive Manufacturing committee and provides peer review to technical publications of AWS and ASM International.  His international technical contributions include US Delegate to the High Energy Beam Welding Commission of the IIW (International Institute of Welding), Invited Keynote Lecturer at the 58th Annual Assembly and International Conference of IIW, and the AWS R.D. Thomas Award winner for his international contributions and committee work on the harmonization of international standards.  

Preface 6
Acknowledgements 11
Contents 12
About the Author 17
Acronyms 19
AM Road Map and Hitchhiker’s Guide 22
1 Envision 24
Abstract 24
1.1 Evolution of Metalworking 25
1.2 Advent of Computers 27
1.3 Invention of 3D Printing 28
1.4 Key Take Away Points 29
2 Additive Manufacturing Metal, the Art of the Possible 30
Abstract 30
2.1 AM Destinations: Novel Applications and Designs 30
2.2 Artistic 32
2.3 Personalized 34
2.4 Medical 36
2.5 Aerospace 39
2.6 Automotive 42
2.7 Industrial Applications Molds and Tooling 44
2.8 Remanufacture and Repair 45
2.9 Scanning and Reverse Engineering 47
2.10 Software 49
2.11 Engineered Structures 50
2.12 Functionally Graded Structures and Intermetallic Materials 51
2.13 Technology Demonstration 53
2.14 Hybrid Additive/Subtractive Systems 54
2.15 Key Take Away Points 55
3 On the Road to AM 57
Abstract 57
3.1 You are Here ? 57
3.2 AM Metal Machines, the Vehicles to Take You There 59
3.3 Market and Technology Drivers 66
3.4 A Pocket Translator: The Language of AM 69
3.5 Key Take Away Points 70
4 Understanding Metal for Additive Manufacturing 71
Abstract 71
4.1 Structure 72
4.1.1 Solid, Liquid, Gas, and Sometimes Plasma 72
4.1.2 Elements and Crystals 73
4.2 Physical Properties 76
4.2.1 Thermal Properties 76
4.2.2 Mechanical Properties 77
4.2.3 Electrical, Magnetic, and Optical Properties 78
4.3 Chemistry and Metallurgy 79
4.3.1 Physical Metallurgy 79
4.3.2 Ease of Fabrication 81
4.3.3 Process Metallurgy 81
4.3.4 Sintered Microstructures 82
4.3.5 Solidification Microstructures 84
4.3.6 Bulk Properties 90
4.4 Forms of Metal 91
4.4.1 Commercial Shapes 91
4.4.2 Metal Powder 93
4.4.3 Wire and Electrodes 99
4.4.4 Graded Materials 100
4.4.5 Composites, Intermetallic, and Metallic Glass 101
4.4.6 Recycled Metal 102
4.4.7 Recycle and Reuse of AM Metal Powders 103
4.5 Key Take Away Points 104
5 Lasers, Electron Beams, Plasma Arcs 106
Abstract 106
5.1 The Molten Pool 106
5.2 Lasers 108
5.3 Electron Beams 111
5.4 Electric and Plasma Arcs 114
5.5 Hybrid Heat Sources 117
5.6 Key Take Away Points 117
6 Computers, Solid Models, and Robots 119
Abstract 119
6.1 Computer-Aided Design 120
6.2 Computer-Aided Engineering 125
6.3 Computer-Aided Manufacturing 129
6.4 Computerized Numerical Control 131
6.5 Robotics 132
6.6 Monitoring and Real-Time Control 134
6.7 Remote Autonomous Operations 135
6.8 Key Take Away Points 136
7 Origins of 3D Metal Printing 138
Abstract 138
7.1 Plastic Prototyping and 3D Printing 139
7.2 Weld Cladding and 3D Weld Metal Buildup 142
7.3 Laser Cladding 144
7.4 Powder Metallurgy 145
7.5 Key Take Away Points 147
8 Current System Configurations 149
Abstract 149
8.1 Laser Beam Powder Bed Fusion Systems 152
8.1.1 Advantages of PBF-L 153
8.1.2 Limitations of PBF-L 158
8.2 Laser Beam Directed Energy Deposition Systems 165
8.2.1 Advantages of DED-L 169
8.2.2 Limitations of DED-L 173
8.3 Additive Manufacturing with Electron Beams 175
8.3.1 Electron Beam Powder Bed Fusion Systems 175
8.4 Electron Beam-Directed Energy Deposition Systems 179
8.5 3D Metal Printing with Arc Welding Systems 184
8.6 Other AM Metal Technology 189
8.6.1 Binder Jet Technology 190
8.6.2 Plastic Tooling in Support of Metal Fabrication 192
8.6.3 Plastic and Wax Printing Combined with Casting 192
8.6.4 Ultrasonic Consolidation 193
8.6.5 Cold Spray Technology 193
8.6.6 Nano and Micro Scale Methods 194
8.7 Key Take Away Points 195
9 Inspiration to 3D Design 198
Abstract 198
9.1 Inspired Design 198
9.2 Elements of Design 201
9.2.1 Material Selection 202
9.2.2 Process Selection 206
9.3 Solid Freeform Design 207
9.3.1 Design Freedom Offered by AM 211
9.3.2 AM Metal Design Constraints 215
9.4 Additional Design Requirements 218
9.4.1 Support Structure Design 218
9.4.2 Design of Fixtures, Jigs, and Tooling 220
9.4.3 Test Specimen Design 221
9.4.4 Prototype Design 221
9.4.5 Hybrid Design 222
9.5 Cost Analysis 222
9.6 Key Take Away Points 226
10 Process Development 227
Abstract 227
10.1 Parameter Selection 227
10.2 Parameter Optimization 232
10.3 Specifying Pre-build and Monitoring Procedures 239
10.3.1 Monitoring of Process Quality 241
10.3.2 In-Process Part Quality Monitoring 242
10.4 Repair or Restart Procedures 243
10.5 Key Take Away Points 244
11 Building, Post-Processing, and Inspecting 245
Abstract 245
11.1 Building the Part 245
11.2 Post-Processing and Finishing 246
11.3 Bulk Deposit Defects 250
11.4 Dimensional Accuracy, Shrinkage, and Distortion 258
11.5 Inspection, Quality, and Testing of AM Metal Parts 258
11.5.1 Nondestructive Test Methods 259
11.5.2 Destructive Test Methods 262
11.5.3 Form, Fit, Function, and Proof Testing 265
11.6 Standards and Certification 266
11.7 Key Take Away Points 268
12 Trends in AM, Government, Industry, Research, Business 270
Abstract 270
12.1 Government and Community 271
12.2 University and Corporate Research 279
12.3 Industrial Applications 283
12.4 Business and Commerce 290
12.5 Intellectual Property, Security, and Regulation 296
12.6 Social and Global Trends 302
12.6.1 Diffusion of Power 304
12.6.2 Demographics, Information, Mobility, Education, Connectivity 304
12.6.3 Food, Water, Energy, Population Growth 305
12.7 Trends in Additive Manufacturing 305
12.7.1 Top AM Technology and Market Destinations 306
12.7.2 The First Steps Toward AM Metal 307
Professional Society and Organization Links 308
AM Machine and Service Resource Links 309
Welding Equipment and Consumables Suppliers 309
Additive Manufacturing Machine Builders and Service Providers 309
Metal Powder Manufacturers 310
Other useful Web Sites with Information, Articles and Links to AM 310
Appendix A: Safety in Configuring a 3D Metal Printing Shop 312
Appendix B: Exercises in Metal Fusion 319
Appendix C: OpenSCAD Programming Example 323
Appendix D: 3D Printer Control Code Example 327
Appendix E: Building an Arc Based 3D Shape Welding System 328
Appendix F: Exercises in 3D Printing 329
Appendix G: Score Chart of AM Skills 332
Glossary 333
References 343
Index 347