Gebhardt / Hötter Additive Manufacturing

3D Printing for Prototyping and Manufacturing
1. Auflage 2016
ISBN: 978-1-56990-664-4
Verlag: Hanser Publications
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 611 Seiten

Oriented towards the practitioner, this book presents a clear overview of additive manufacturing, going from the basics to the properties and special aspects of industrially available machines. From the generation of data to the forming method, the complete process chain is shown in a practical light. In particular, the following additive manufacturing technologies are discussed extensively:
- Polymerization (e.g., stereolithography)
- Sintering and melting (e.g., laser sintering)
- Layer laminate method (e.g., laminated object manufacturing, LOM)
- Extrusion (e.g., fused deposition modeling, FDM)
- 3D printing
Applications for the production of models and prototypes (rapid prototyping), tools, tool inserts, and forms (rapid tooling) as well as end products (rapid manufacturing) are covered in detailed chapters with examples. Questions of efficiency are discussed from a strategic point of view, and also from an operational perspective.
This book was written to support product developers and people responsible for production who face the challenges of implementing additive manufacturing not just for prototypes or one-off parts, but for its increaingly important application in direct production of finished products. The method not only reduces the demands on industrial infrastructure, but also opens up new perspectives in terms of decentralized production and customer inclusive individualized production (customization, cyberproduction).

Dr.-Ing. Andreas Gebhardt studierte an der technischen Hochschule Aachen Maschinenbau mit dem Schwerpunkt Motoren- und Turbinenbau. Nach Stationen als Geschäftsführer in der mittelständischen Wirtschaft wurde er zum Sommersemester 2000 als Professor für Hochleistungsverfahren der Fertigungstechnik und Rapid Prototyping an die Fachhochschule Aachen berufen. Dort leitet er eine Forschergruppe und Labore zum Lasersintern von Metallen (SLM Verfahren), Polymerdrucken, 3D-Drucken (Pulver-Binder Verfahren), Extrusionsverfahren (FDM) und zum Einsatz unterschiedlicher Fabber. Seit dem Wintersemester 2000 ist Andreas Gebhardt Gastprofessor am City College der City University New York. 2004 gründete er das RTeJournal (www.rtejournal.de), eine 'open-access' online-Zeitschrift für Rapid Technology und ist dessen Herausgeber.

Autoren/Hrsg.

Gebhardt, Andreas

Hötter, Jan-Steffen

Inhaltsverzeichnis

1;Foreword;7
2;About the Authors;9
3;Acknowledgements;11
4;Contents;13
5;1 Basics, Definitions, and Application Levels;23
5.1;1.1 Systematics of Manufacturing Technologies;23
5.2;1.2 Systematics of Layer Technology;24
5.2.1;1.2.1 Application of Layer Technology: Additive Manufacturing and 3D Printing;25
5.2.2;1.2.2 Characteristics of Additive Manufacturing;25
5.3;1.3 Hierarchical Structure of Additive Manufacturing Processes;28
5.3.1;1.3.1 Rapid Prototyping;29
5.3.2;1.3.2 Rapid Manufacturing;31
5.3.2.1;1.3.2.1 Rapid Manufacturing—Direct Manufacturing;31
5.3.2.2;1.3.2.2 Rapid Manufacturing—Rapid Tooling (Direct Tooling— Prototype Tooling);32
5.3.3;1.3.3 Related Nonadditive Processes: Indirect or Secondary Rapid Prototyping Processes;32
5.3.4;1.3.4 Rapid Prototyping or Rapid Manufacturing?;33
5.3.5;1.3.5 Diversity of Terms;34
5.3.6;1.3.6 How Fast Is Rapid?;35
5.4;1.4 Integration of Additive Manufacturing in the Product Development Process;35
5.4.1;1.4.1 Additive Manufacturing and Product Development;35
5.4.2;1.4.2 Additive Manufacturing for Low-Volume and One-of-a-Kind Production;37
5.4.3;1.4.3 Additive Manufacturing for Individualized Production;37
5.5;1.5 Machines for Additive Manufacturing;38
6;2 Characteristics of the Additive Manufacturing Process;43
6.1;2.1 Basic Principles of the Additive Manufacturing Process;43
6.2;2.2 Generation of Layer Information;48
6.2.1;2.2.1 Description of the Geometry by a 3D Data Record;48
6.2.1.1;2.2.1.1 Data Flow and Interfaces;48
6.2.1.2;2.2.1.2 Modeling 3D Bodies in a Computer by Means of 3D CAD;50
6.2.1.3;2.2.1.3 Generating 3D Models from Measurements;54
6.2.2;2.2.2 Generation of Geometrical Layer Information on Single Layers;55
6.2.2.1;2.2.2.1 STL Format;56
6.2.2.2;2.2.2.2 CLI/SLC Format;60
6.2.2.3;2.2.2.3 PLY and VRML Formats;63
6.2.2.4;2.2.2.4 AMF Format;65
6.3;2.3 Physical Principles for Layer Generation;66
6.3.1;2.3.1 Solidification of Liquid Materials;67
6.3.1.1;2.3.1.1 Photopolymerization?Stereolithography (SL);67
6.3.1.2;2.3.1.2 Basic Principles of Polymerization;68
6.3.2;2.3.2 Generation from the Solid Phase;79
6.3.2.1;2.3.2.1 Melting and Solidification of Powders and Granules: Laser Sintering (LS);79
6.3.2.2;2.3.2.2 Cutting from Foils: Layer Laminate Manufacturing (LLM);87
6.3.2.3;2.3.2.3 Melting and Solidification out of the Solid Phase: Fused Layer Modeling (FLM);88
6.3.2.4;2.3.2.4 Conglutination of Granules and Binders: 3D Printing;91
6.3.3;2.3.3 Solidification from the Gas Phase;93
6.3.3.1;2.3.3.1 Aerosol Printing Process;93
6.3.3.2;2.3.3.2 Laser Chemical Vapor Deposition (LCVD);94
6.3.4;2.3.4 Other Processes;95
6.3.4.1;2.3.4.1 Sonoluminescence;95
6.3.4.2;2.3.4.2 Electroviscosity;96
6.4;2.4 Elements for Generating the Physical Layer;96
6.4.1;2.4.1 Moving Elements;96
6.4.1.1;2.4.1.1 Plotter;96
6.4.1.2;2.4.1.2 Scanner;97
6.4.1.3;2.4.1.3 Simultaneous Robots (Delta Robots);98
6.4.2;2.4.2 Generating and Contouring Elements;98
6.4.2.1;2.4.2.1 Laser;99
6.4.2.2;2.4.2.2 Nozzles;101
6.4.2.3;2.4.2.3 Extruder;103
6.4.2.4;2.4.2.4 Cutting Blade;104
6.4.2.5;2.4.2.5 Milling Cutter;104
6.4.3;2.4.3 Layer-Generating Element;105
6.5;2.5 Classification of Additive Manufacturing Processes;106
6.6;2.6 Summary Evaluation of the Theoretical Potentials of Rapid Prototyping Processes;108
6.6.1;2.6.1 Materials;109
6.6.2;2.6.2 Model Properties;110
6.6.3;2.6.3 Details;111
6.6.4;2.6.4 Accuracy;112
6.6.5;2.6.5 Surface Quality;112
6.6.6;2.6.6 Development Potential;113
6.6.7;2.6.7 Continuous 3D Model Generation;113
7;3 Machines for Rapid Prototyping, Direct Tooling, and Direct Manufacturing;115
7.1;3.1 Polymerization: Stereolithography (SL);119
7.1.1;3.1.1 Machine-Specific Basis;119
7.1.1.1;3.1.1.1 Laser Stereolithography;119
7.1.1.2;3.1.1.2 Digital Light Processing;129
7.1.1.3;3.1.1.3 PolyJet and MultiJet Modeling and Paste Polymerization;130
7.1.2;3.1.2 Overview: Polymerization, Stereolithography;130
7.1.3;3.1.3 Stereolithography Apparatus (SLA), 3D Systems;132
7.1.4;3.1.4 STEREOS, EOS;142
7.1.5;3.1.5 Stereolithography, Fockele & Schwarze;143
7.1.6;3.1.6 Microstereolithography, microTEC;144
7.1.7;3.1.7 Solid Ground Curing, Cubital;147
7.1.8;3.1.8 Digital Light Processing, Envisiontec;148
7.1.9;3.1.9 Polymer Printing, Stratasys/Objet;154
7.1.10;3.1.10 Multijet Modeling (MJM), ProJet, 3D Systems;159
7.1.11;3.1.11 Digital Wax;162
7.1.12;3.1.12 Film Transfer Imaging, 3D Systems;165
7.1.13;3.1.13 Other Polymerization Processes;168
7.1.13.1;3.1.13.1 Paste Polymerization, OptoForm;168
7.2;3.2 Sintering/Selective Sintering: Melting in the Powder Bed;168
7.2.1;3.2.1 Machine-Specific Basic Principles;168
7.2.2;3.2.2 Overview: Sintering and Melting;173
7.2.3;3.2.3 Selective Laser Sintering, 3D Systems/DTM;175
7.2.4;3.2.4 Laser Sintering, EOS;187
7.2.5;3.2.5 Laser Melting, Realizer GmbH;198
7.2.6;3.2.6 Laser Sintering, SLM Solutions;202
7.2.7;3.2.7 Laser Melting, Renishaw Ltd.;204
7.2.8;3.2.8 Laser Cusing, Concept Laser;207
7.2.9;3.2.9 Direct Laser Forming, TRUMPF;213
7.2.10;3.2.10 Electron Beam Melting;214
7.2.11;3.2.11 Selective Mask Sintering (SMS), Sintermask;219
7.2.12;3.2.12 Laser Sintering, Phenix;222
7.3;3.3 Coating: Melting with the Powder Nozzle;225
7.3.1;3.3.1 Process Principle;225
7.3.1.1;3.3.1.1 Concepts of Powder Nozzles;227
7.3.1.2;3.3.1.2 Process Monitoring and Control;228
7.3.2;3.3.2 Laser-Engineered Net Shaping (LENS), Optomec;228
7.3.3;3.3.3 Direct Metal Deposition (DMD), DM3D Technology (TRUMPF);231
7.4;3.4 Layer Laminate Manufacturing (LLM);235
7.4.1;3.4.1 Overview of Layer Laminate Manufacturing;235
7.4.2;3.4.2 Machine-Specific Basics;236
7.4.3;3.4.3 Laminated Object Manufacturing (LOM), Cubic Technologies;240
7.4.4;3.4.4 Rapid Prototyping Systems (RPS), Kinergy;245
7.4.5;3.4.5 Selective Adhesive and Hot Press Process (SAHP), Kira;246
7.4.6;3.4.6 Layer Milling Process (LMP), Zimmermann;247
7.4.7;3.4.7 Stratoconception, rp2i;247
7.4.8;3.4.8 Paper 3D Printing, MCor;248
7.4.9;3.4.9 Plastic Sheet Lamination, Solido;250
7.4.10;3.4.10 Other Layer Laminate Methods;253
7.4.10.1;3.4.10.1 Parts of Metal Foils: Laminated Metal Prototyping;253
7.5;3.5 Extrusion: Fused Layer Modeling (FLM);254
7.5.1;3.5.1 Overview of Extrusion Processes;254
7.5.2;3.5.2 Fused Deposition Modeling (FDM), Stratasys;255
7.5.3;3.5.3 Wax Printers, Solidscape;266
7.5.4;3.5.4 Multijet Modeling (MJM), ThermoJet, 3D Systems;269
7.6;3.6 Three-Dimensional Printing (3DP);270
7.6.1;3.6.1 Overview: 3D Printing;270
7.6.2;3.6.2 3D Printer, 3D Systems, and Z Corporation;270
7.6.3;3.6.3 Metal and Molding Sand Printer, ExOne;275
7.6.3.1;3.6.3.1 Metal Line: Direct Metal Printer;277
7.6.3.2;3.6.3.2 Molding Sand Line: Direct Core and Mold-Making Machine;279
7.6.4;3.6.4 Direct Shell Production Casting (DSPC), Soligen;281
7.6.5;3.6.5 3D Printing System, Voxeljet;285
7.6.6;3.6.6 Maskless Mesoscale Material Deposition (M3D), Optomec;289
7.7;3.7 Hybrid Processes;291
7.7.1;3.7.1 Controlled Metal Buildup (CMB);292
7.7.2;3.7.2 Laminating and Ultrasonic Welding: Ultrasonic Consolidation, Solidica;294
7.8;3.8 Summary Evaluation of Rapid Prototyping Processes;298
7.8.1;3.8.1 Characteristic Properties of AM Processes Compared to Conventional Processes;298
7.8.2;3.8.2 Accuracy;301
7.8.3;3.8.3 Surfaces;304
7.8.4;3.8.4 Benchmark Tests and User Parts;307
7.9;3.9 Planning Targets;310
7.10;3.10 Follow-up Processes;311
7.10.1;3.10.1 Target Material: Plastics;311
7.10.2;3.10.2 Target Material: Metal;312
8;4 Rapid Prototyping;313
8.1;4.1 Classification and Definition;313
8.1.1;4.1.1 Properties of Prototypes;313
8.1.2;4.1.2 Characteristics of Rapid Prototyping;314
8.2;4.2 Strategic Aspects for the Use of Prototypes;315
8.2.1;4.2.1 Product Development Steps;315
8.2.2;4.2.2 Time to Market;316
8.2.3;4.2.3 Front Loading;317
8.2.4;4.2.4 Digital Product Model;320
8.2.5;4.2.5 The Limits of Physical Modeling;321
8.2.6;4.2.6 Communication and Motivation;322
8.3;4.3 Operational Aspects in the Use of Prototypes;323
8.3.1;4.3.1 Rapid Prototyping as a Tool for Fast Product Development;323
8.3.1.1;4.3.1.1 Models;323
8.3.1.2;4.3.1.2 Model Classes;324
8.3.1.3;4.3.1.3 Model Classes and Additive Processes;327
8.3.1.4;4.3.1.4 Assignment of Model Classes and Model Properties to the Families of Additive Production Processes;331
8.3.2;4.3.2 Applications of Rapid Prototyping in Industrial Product Development;334
8.3.2.1;4.3.2.1 Example: Housing of a Pump;334
8.3.2.2;4.3.2.2 Example: Office L335
8.3.2.3;4.3.2.3 Example: Recessed Lighting Socket;339
8.3.2.4;4.3.2.4 Example: Model Digger Arm;340
8.3.2.5;4.3.2.5 Example: LCD Projector;344
8.3.2.6;4.3.2.6 Example: Capillary Bottom for Flower Pots;345
8.3.2.7;4.3.2.7 Example: Casing for a Coffeemaker;346
8.3.2.8;4.3.2.8 Example: Intake Manifold of a Four-Cylinder Engine;347
8.3.2.9;4.3.2.9 Example: Cocktail Glass;348
8.3.2.10;4.3.2.10 Example: Mirror Triangle;349
8.3.2.11;4.3.2.11 Example: Convertible Top;349
8.3.3;4.3.3 Rapid Prototyping Models for the Visualization of 3D Data;353
8.3.4;4.3.4 Rapid Prototyping in Medicine;354
8.3.4.1;4.3.4.1 Characteristics of Medical Models;354
8.3.4.2;4.3.4.2 Anatomic Facsimile Models;355
8.3.4.3;4.3.4.3 Example: Anatomic Facsimiles for a Reconstructive Osteotomy;357
8.3.5;4.3.5 Rapid Prototyping in Art, Archaeology, and Architecture;358
8.3.5.1;4.3.5.1 Model Making in Art and Design, General;358
8.3.5.2;4.3.5.2 Example of Art: Computer Sculpture, Georg Glückman;359
8.3.5.3;4.3.5.3 Example of Design: Bottle Opener;359
8.3.5.4;4.3.5.4 Applied Art: Statuary and Sculpture;361
8.3.5.5;4.3.5.5 Example of Archaeology: Bust of Queen Teje;362
8.3.5.6;4.3.5.6 Model Building in Architecture, General;363
8.3.5.7;4.3.5.7 Example of Architecture: German Pavilion at Expo ’92;364
8.3.5.8;4.3.5.8 Example of Architecture: Ground Zero;364
8.3.5.9;4.3.5.9 Example of Architectural Monuments: Documentation of Buildings Relevant to Architectural History;366
8.3.6;4.3.6 Rapid Prototyping for the Evaluation of Calculation Methods;367
8.3.6.1;4.3.6.1 Photoelastic and Thermoelastic Stress Analysis;367
8.3.6.2;4.3.6.2 Example: Photoelastic Stress Analysis for a Cam Rod in the Engine of a Truck;370
8.3.6.3;4.3.6.3 Example: Thermoelastic Stress Analysis for Verifying the Stability of a Car Wheel Rim;371
8.4;4.4 Outlook;374
9;5 Rapid Tooling;375
9.1;5.1 Classification and Definition of Terms;375
9.1.1;5.1.1 Direct and Indirect Methods;376
9.2;5.2 Properties of Additive Manufactured Tools;377
9.2.1;5.2.1 Strategic Aspects for the Use of Additive Manufactured Tools;378
9.2.1.1;5.2.1.1 Speed;378
9.2.1.2;5.2.1.2 Implementation of New Technical Concepts;378
9.2.2;5.2.2 Design Properties of Additive Manufactured Tools;380
9.2.2.1;5.2.2.1 Prototype Tools;380
9.2.2.2;5.2.2.2 Supply of Data;383
9.3;5.3 Indirect Rapid Tooling Processes: Molding Processes and Follow-up Processes;385
9.3.1;5.3.1 Suitability of AM Processes for the Manufacture of Master Patterns for Subsequent Processes;385
9.3.2;5.3.2 Indirect Methods for the Manufacture of Tools for Plastic Components;387
9.3.2.1;5.3.2.1 Casting in Soft Tools or Molds;387
9.3.2.2;5.3.2.2 Casting into Hard Tools;392
9.3.2.3;5.3.2.3 Other Molding Techniques for Hard Tools;396
9.3.3;5.3.3 Indirect Methods for the Manufacture of Metal Components;397
9.3.3.1;5.3.3.1 Investment Casting with AM Process Steps;397
9.3.3.2;5.3.3.2 Tools by Investment Casting of Rapid Prototyping Master Models;400
9.4;5.4 Direct Rapid Tooling Processes;401
9.4.1;5.4.1 Prototype Tooling: Tools Based on Plastic Rapid Prototyping Models and Methods;401
9.4.1.1;5.4.1.1 ACES Injection Molding;401
9.4.1.2;5.4.1.2 Deep Drawing or Thermoforming;402
9.4.1.3;5.4.1.3 Casting of Rapid Prototyping Models;403
9.4.1.4;5.4.1.4 Manufacture of Cores and Molds for Metal Casting;404
9.4.2;5.4.2 Metal Tools Based on Multilevel AM Processes;405
9.4.2.1;5.4.2.1 Selective Laser Sintering of Metals: IMLS by 3D Systems;405
9.4.2.2;5.4.2.2 Paste Polymerization: OptoForm;406
9.4.2.3;5.4.2.3 3D Printing of Metals: ExOne;406
9.4.3;5.4.3 Direct Tooling: Tools Based on Metal Rapid Prototype Processes;407
9.4.3.1;5.4.3.1 Multicomponent Metal Powder Laser Sintering;407
9.4.3.2;5.4.3.2 Single-Component Metal Powder Methods: Sintering and Additive Manufacturing;408
9.4.3.3;5.4.3.3 Laser Generating with Powder and Wire;413
9.4.3.4;5.4.3.4 Layer Laminate Process, Metal Blade Tools, Laminated Metal Tooling;415
9.5;5.5 Future Prospects;416
10;6 Direct Manufacturing: Rapid Manufacturing;417
10.1;6.1 Classification and Definition of Terms;417
10.1.1;6.1.1 Terms;418
10.1.2;6.1.2 From Rapid Prototyping to Rapid Manufacturing;419
10.1.3;6.1.3 Workflow for Direct Manufacturing;420
10.1.4;6.1.4 Requirements for Direct Manufacturing;420
10.2;6.2 Potential for Additive Manufacturing of End Products;421
10.2.1;6.2.1 Increased Design Freedom;421
10.2.1.1;6.2.1.1 Advanced Design and Structural Opportunities;421
10.2.1.2;6.2.1.2 Functional Integration;422
10.2.1.3;6.2.1.3 Novel Design Elements;423
10.2.2;6.2.2 Production of Traditionally Not Producible Products;423
10.2.3;6.2.3 Variation of Mass Products;424
10.2.4;6.2.4 Personalization of Mass Products;425
10.2.4.1;6.2.4.1 Passive Personalization: Manufacturer Personalization;426
10.2.4.2;6.2.4.2 Active Personalization: Customer Personalization;428
10.2.5;6.2.5 Realization of New Materials;429
10.2.6;6.2.6 Realization of New Manufacturing Strategies;429
10.2.7;6.2.7 Design of New Labor and Living Alternatives;430
10.3;6.3 Requirements on Additive Manufacturing for Production;431
10.3.1;6.3.1 Requirements on Additive Manufacturing of a Part;432
10.3.1.1;6.3.1.1 Process;432
10.3.1.2;6.3.1.2 Materials;433
10.3.1.3;6.3.1.3 Organization;435
10.3.1.4;6.3.1.4 Design;435
10.3.1.5;6.3.1.5 Quality Assurance;436
10.3.1.6;6.3.1.6 Logistics;436
10.3.2;6.3.2 Requirements for Additive Mass Production with Current Methods;436
10.3.2.1;6.3.2.1 Process;437
10.3.2.2;6.3.2.2 Materials;439
10.3.2.3;6.3.2.3 Organization;439
10.3.2.4;6.3.2.4 Design;440
10.3.2.5;6.3.2.5 Quality Assurance;440
10.3.2.6;6.3.2.6 Logistics;440
10.3.3;6.3.3 Future Efforts in Additive Series Production;440
10.3.3.1;6.3.3.1 Process;441
10.3.3.2;6.3.3.2 Materials;443
10.3.3.3;6.3.3.3 Organization;444
10.3.3.4;6.3.3.4 Design;444
10.3.3.5;6.3.3.5 Quality Assurance;445
10.3.3.6;6.3.3.6 Logistics;446
10.4;6.4 Implementation of Rapid Manufacturing;446
10.4.1;6.4.1 Additive Manufacturing Machines as Elements of a Process Chain;447
10.4.2;6.4.2 Additive Machines for Complete Production of Products;448
10.4.2.1;6.4.2.1 Industrial Complete Production;448
10.4.2.2;6.4.2.2 Individual Complete Production (Personal Fabrication);450
10.5;6.5 Application Fields;451
10.5.1;6.5.1 Application Fields for Materials;452
10.5.1.1;6.5.1.1 Metallic Materials and Alloys;452
10.5.1.2;6.5.1.2 High-Performance Ceramics;453
10.5.1.3;6.5.1.3 Plastics;454
10.5.1.4;6.5.1.4 New Materials;455
10.5.2;6.5.2 Application Fields by Industry;455
10.5.2.1;6.5.2.1 Tooling;455
10.5.2.2;6.5.2.2 Casting;457
10.5.2.3;6.5.2.3 Medical Equipment and Aids, Medical Technology;460
10.5.2.4;6.5.2.4 Design and Art;465
10.6;6.6 Summary;470
11;7 Safety and Environmental Protection;473
11.1;7.1 Labor Agreements for the Operation and Production of Additive Manufacturing Machines and the Handling of the Corresponding Material;474
11.2;7.2 Annotations to Materials for Additive Manufacturing;475
11.3;7.3 Annotations for Using Additive Manufactured Components;476
12;8 Economic Aspects;479
12.1;8.1 Strategic Aspects;480
12.1.1;8.1.1 Strategic Aspects of the Use of AM Methods in Product Development;480
12.1.1.1;8.1.1.1 Qualitative Approaches;480
12.1.1.2;8.1.1.2 Quantitative Approaches;481
12.2;8.2 Operative Aspects;482
12.2.1;8.2.1 Establishing the Optimal Additive Manufacturing Process;482
12.2.2;8.2.2 Establishing the Costs of Additive Manufacturing Processes;483
12.2.2.1;8.2.2.1 Variable Costs;484
12.2.2.2;8.2.2.2 Fixed Costs;486
12.2.3;8.2.3 Characteristics of Additive Manufacturing and Its Impacts on Economy;489
12.2.3.1;8.2.3.1 Construction Time;489
12.2.3.2;8.2.3.2 Lot Sizes and Use of Construction Space;489
12.2.3.3;8.2.3.3 Utilization;490
12.2.3.4;8.2.3.4 Material Consumption;490
12.2.3.5;8.2.3.5 Process Safety;491
12.2.3.6;8.2.3.6 Construction Speed;491
12.2.3.7;8.2.3.7 Technical Progress and Model Refinement;493
12.2.3.8;8.2.3.8 Service;493
12.3;8.3 Make or Buy?;494
13;9 Future Rapid Prototyping Processes;497
13.1;9.1 Microcomponents;497
13.1.1;9.1.1 Microcomponents Made of Metal and Ceramic;497
13.1.2;9.1.2 Microcomponents Made of Metal and Ceramics by Laser Melting;498
13.1.2.1;9.1.2.1 Melting Process in Selective Laser Melting;498
13.1.2.2;9.1.2.2 Microstructures of Metal Powder;499
13.1.2.3;9.1.2.3 Microstructures of Ceramic Powder;502
13.2;9.2 Contour Crafting;504
13.3;9.3 D-Shape Process;506
13.4;9.4 Selective Inhibition of Sintering (SIS);509
13.4.1;9.4.1 The SIS-Polymer Process;509
13.4.2;9.4.2 The SIS-Metal Process;511
13.5;9.5 Free Molding;513
13.6;9.6 Freeformer;514
14;Appendix;515
14.1;Glossary;591
15;Bibliography;597
16;Index;603
17;Leere Seite;2

Leseproben

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.

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.

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:

• The geometry of each layer is obtained solely and directly from the 3D computer-aided design (CAD) data of the part (commonly called a virtual product model).

• There are no product-related tools necessary and consequently no tool change.

• The material properties of the part are generated during the build process.

• The 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.

• Today, 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.

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.

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...

Über Autor(innen)

Gebhardt, Andreas
Dr.-Ing. Andreas Gebhardt studierte an der technischen Hochschule Aachen Maschinenbau mit dem Schwerpunkt Motoren- und Turbinenbau. Nach Stationen als Geschäftsführer in der mittelständischen Wirtschaft wurde er zum Sommersemester 2000 als Professor für Hochleistungsverfahren der Fertigungstechnik und Rapid Prototyping an die Fachhochschule Aachen berufen. Dort leitet er eine Forschergruppe und Labore zum Lasersintern von Metallen (SLM Verfahren), Polymerdrucken, 3D-Drucken (Pulver-Binder Verfahren), Extrusionsverfahren (FDM) und zum Einsatz unterschiedlicher Fabber. Seit dem Wintersemester 2000 ist Andreas Gebhardt Gastprofessor am City College der City University New York.
2004 gründete er das RTeJournal (www.rtejournal.de), eine „open-access“ online-Zeitschrift für Rapid Technology und ist dessen Herausgeber.