1.8.3 Haptic-Based CAD 1.9 About this Book 1.10 Exercises References Development of Additive Manufacturing Technology

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1 Contents 1 Introduction and Basic Principles What Is Additive Manufacturing? What Are AM Parts Used for? The Generic AM Process Step 1: CAD Step 2: Conversion to STL Step 3: Transfer to AM Machine and STL File Manipulation Step 4: Machine Setup Step 5: Build Step 6: Removal Step 7: Post-processing Step 8: Application Why Use the Term Additive Manufacturing? Automated Fabrication (Autofab) Freeform Fabrication or Solid Freeform Fabrication Additive Manufacturing or Layer-Based Manufacturing Stereolithography or 3D Printing Rapid Prototyping The Benefits of AM Distinction Between AM and CNC Machining Material Speed Complexity Accuracy Geometry Programming Example AM Parts Other Related Technologies Reverse Engineering Technology Computer-Aided Engineering 15

2 1.8.3 Haptic-Based CAD 1.9 About this Book 1.10 Exercises References Development of Additive Manufacturing Technology Introduction 19 ">0 2.2 Computers 2.3 Computer-Aided Design Technology ~~ 2.4 Other Associated Technologies Lasers Printing Technologies Programmable Logic Controllers Materials Computer Numerically Controlled Machining The Use of Layers Classification of AM Processes Liquid Polymer Systems Discrete Particle Systems Molten Material Systems Solid Sheet Systems New AM Classification Schemes Metal Systems Hybrid Systems Milestones in AM Development AM Around the World The Future? Rapid Prototyping Develops into Direct Digital Manufacturing Exercises 41 References 41 Generalized Additive Manufacturing Process Chain Introduction The Eight Steps in Additive Manufacture Step 1: Conceptualization and CAD Step 2: Conversion to STL/AMP Step 3: Transfer to AM Machine and STL File Manipulation Step 4: Machine Setup Step 5: Build Step 6: Removal and Cleanup Step 7: Post-Processing Step 8: Application Variations from One AM Machine to Another Photopolymer-Based Systems 51

3 3.3.2 Powder-Based Systems Molten Material Systems Solid Sheets Metal Systems The Use of Substrates Energy Density Weight Accuracy Speed Maintenance of Equipment Materials Handling Issues Design for AM Part Orientation Removal of Supports Hollowing Out Parts Inclusion of Undercuts and Other Manufacturing Constraining Features Interlocking Features Reduction of Part Count in an Assembly Identification Markings/Numbers Application Areas That Don't Involve Conventional CAD Modeling Medical Modeling Reverse Engineering Data Architectural Modeling Further Discussion Exercises 61 References 61 4 Vat Photopolymerization Processes Introduction Vat Photopolymerization Materials UV-Curable Photopolymers Overview of Photopolymer Chemistry Resin Formulations and Reaction Mechanisms Reaction Rates Laser Scan Vat Photopolymerization Photopolymerization Process Modeling Irradiance and Exposure Laser-Resin Interaction Photospeed Time Scales Vector Scan VP Machines Scan Patterns Layer-Based Build Phenomena and Errors 84

4 4.7.2 WEAVE STAR-WEAVE ACES Scan Pattern Vector Scan Micro-Vat Photopolymerization Mask Projection VP Technologies and Processes Mask Projection VP Technology Commercial MPVP Systems MPVP Modeling Two-Photon Vat Photopolymerization Process Benefits and Drawbacks Summary 4.13 Exercises References ' ^ 5 Powder Bed Fusion Processes ' Introduction ' Materials ' Polymers and Composites Metals and Composites Ceramics and Ceramic Composites Powder Fusion Mechanisms Solid-State Sintering Chemically Induced Sintering LPS and Partial Melting Full Melting Part Fabrication Process Parameters and Modeling Process Parameters Applied Energy Correlations and Scan Patterns Powder Handling Powder Handling Challenges Powder Handling Systems Powder Recycling PBF Process Variants and Commercial Machines Polymer Laser Sintering Laser-Based Systems for Metals and Ceramics Electron Beam Melting Line-Wise and Layer-Wise PBF Processes for Polymers Process Benefits and Drawbacks Conclusions Exercises 144 References 145

5 6 Extrusion-Based Systems Introduction Basic Principles Material Loading Liquidation Extrusion Solidification Positional Control Bonding Support Generation Plotting and Path Control Fused Deposition Modeling from Stratasys FDM Machine Types Materials Limitations of FDM Bioextrusion Gel Formation Melt Extrusion Scaffold Architectures Other Systems Contour Crafting Nonplanar Systems FDM of Ceramics Reprap and Exercises 172 References Material Jetting Evolution of Printing as an Additive Manufacturing Process Materials for Material Jetting Polymers Ceramics Metals Solution-and Dispersion-Based Deposition Material Processing Fundamentals Technical Challenges of MJ Droplet Formation Technologies Continuous Mode DOD Mode Other Droplet Formation Methods MJ Process Modeling Material Jetting Machines Process Benefits and Drawbacks Summary Exercises 199 References 200

6 8 Binder Jetting 20 s ) ' 8.1 Introduction ~ _ 8.2 Materials ~ Commercially Available Materials -,) Ceramic Materials in Research Process Vanations I BJ Machines ~~ 8 5 Process Benefits and Drawbacks - "> Summary Exercises - References ~^ 9 Sheet Lamination Processes Introduction Gluing or Adhesive Bonding Bond-Then-Form Processes Form-Then-Bond Processes Materials Material Processing Fundamentals Thermal Bonding Sheet Metal Clamping Ultrasonic Additive Manufacturing UAM Bond Quality Ultrasonic Metal Welding Process Fundamentals UAM Process Parameters and Process Optimization Microstructures and Mechanical Properties of UAM Parts UAM Applications Conclusions Exercises 243 References Directed Energy Deposition Processes Introduction General DED Process Description Material Delivery Powder Feeding Wire Feeding DED Systems Laser Based Metal Deposition Processes Electron Beam Based Metal Deposition Processes Other DED Processes Process Parameters Typical Materials and Microstructure 258

7 10.7 Processing-Structure-Properties Relationships DED Benefits and Drawbacks Exercises 267 References Direct Write Technologies Direct Write Technologies Background Ink-Based DW Nozzle Dispensing Processes Quill-Type Processes Inkjet Printing Processes Aerosol DW Laser Transfer DW Thermal Spray DW Beam Deposition DW Laser CVD Focused Ion Beam CVD Electron Beam CVD Liquid-Phase Direct Deposition Beam Tracing Approaches to Additive/Subtractive DW Electron Beam Tracing Focused Ion Beam Tracing Laser Beam Tracing Hybrid Technologies Applications of Direct Write Technologies Exercises 290 References The Impact of Low-Cost AM Systems Introduction Intellectual Property Disruptive Innovation Disruptive Business Opportunities Media Attention The Maker Movement The Future of Low-Cost AM Exercises 301 References Guidelines for Process Selection Introduction Selection Methods for a Part Decision Theory Approaches to Determining Feasibility Approaches to Selection Selection Example 310

8 13.3 Challenges of Selection Example System for Preliminary Selection Production Planning and Control Production Planning Pre-processing Part Build Post-processing Summary Open Problems Exercises 32^ References 32^ 14 Post-processing Introduction Support Material Removal Natural Support Post-processing Synthetic Support Removal Surface Texture Improvements Accuracy Improvements Sources of Inaccuracy Model Pre-processing to Compensate for Inaccuracy Machining Strategy Aesthetic Improvements Preparation for Use as a Pattern Investment Casting Patterns Sand Casting Patterns Other Pattern Replication Methods Property Enhancements Using Non-thermal Techniques Property Enhancements Using Thermal Techniques Conclusions Exercises 349 References Software Issues for Additive Manufacturing Introduction Preparation of CAD Models: The STL File STL File Format, Binary/ASCII Creating STL Files from a CAD System Calculation of Each Slice Profile Technology-Specific Elements Problems with STL Files STL File Manipulation Viewers STL Manipulation on the AM Machine 365

9 15.5 Beyond the STL File Direct Slicing of the CAD Model Color Models Multiple Materials Use of STL for Machining Additional Software to Assist AM Survey of Software Functions AM Process Simulations Using Finite Element Analysis The Additive Manufacturing File Format Exercises 373 References Direct Digital Manufacturing Align Technology Siemens and Phonak Custom Footwear and Other DDM Examples DDM Drivers Manufacturing Versus Prototyping Cost Estimation Cost Model Build Time Model Laser Scanning Vat Photopolymerization Example Life-Cycle Costing Future of DDM Exercises 396 References Design for Additive Manufacturing Motivation Design for Manufacturing and Assembly AM Unique Capabilities Shape Complexity Hierarchical Complexity Functional Complexity Material Complexity Core DFAM Concepts and Objectives Complex Geometry Integrated Assemblies Customized Geometry Multifunctional Designs Elimination of Conventional DFM Constraints 413

10 17.5 Exploring Design Freedoms 4 -^ Part Consolidation and Redesign Hierarchical Structures Industrial Design Applications CAD Tools for AM Challenges for CAD Solid-Modeling CAD Systems Promising CAD Technologies Synthesis Methods 4 ~^ Theoretically Optimal Lightweight Structures Optimization Methods Topology Optimization Summary 4^ 17.9 Exercises 424 References Rapid Tooling 4^ Introduction 4^ Direct AM Production of Injection Molding Inserts EDM Electrodes Investment Casting Other Systems Vacuum Forming Tools Paper Pulp Molding Tools Formwork for Composite Manufacture Assembly Tools and Metrology Registration Rigs Exercises 448 References Applications for Additive Manufacture Introduction Historical Developments Value of Physical Models Functional Testing Rapid Tooling The Use of AM to Support Medical Applications Surgical and Diagnostic Aids Prosthetics Development Manufacturing Tissue Engineering and Organ Printing Software Support for Medical Applications 461

11 19.5 Limitations of AM for Medical Applications Speed Cost Accuracy Materials Ease of Use Further Development of Medical AM Applications Approvals Insurance Engineering Training Location of the Technology Service Bureaus Aerospace Applications Characteristics Favoring AM Production Manufacture Automotive Applications Exercises 473 References Business Opportunities and Future Directions Introduction What Could Be New? New Types of Products New Types of Organizations New Types of Employment Digiproneurship Exercises 485 References 486 Index 487