Micro Metal Forming (eBook)

Preface 5
Authors 8
Contents 10
Global Variables 12
305433_1_En_1_Chapter_OnlinePDF 14
1 Introduction 14
Reference 16
2 Basic Aspects 17
2.1…Size Effects 19
2.1.1 Definition and Categories 19
2.1.2 Density EffectsDensity effects 24
2.1.3 Shape EffectsShape effects 26
2.1.4 Structure EffectsStructure effects 29
2.2…Tribology 32
2.2.1 FrictionFriction 32
2.2.1.1 Tribological SystemTribological system 32
2.2.1.2 Characteristics of Friction 33
2.2.1.3 Testing Methods 34
Ring Compression Test 35
Double Cup Extrusion Test 35
Compression Sliding Test 36
Double Deflection Stripe Drawing Test 36
2.2.1.4 Effects of Miniaturization on Friction 38
2.2.1.5 Lubricant Pocket ModelLubricant pocket model 40
2.2.1.6 Velocity Dependence of Friction 42
2.2.2 Tool Wear 44
2.3…Formability 50
2.3.1 Measures for Formability 50
2.3.2 Formability in Micro Metal Forming 53
Reference 57
3 Mechanical Properties 60
3.1…Development of Microstructure 62
3.1.1 Microstructural Size Effects 62
3.1.2 Grain Structure 62
3.1.2.1 Grain Structures in Thin Sheets 63
3.1.2.2 Normal Grain GrowthNormal Grain Growth 64
3.1.2.3 Orientation-Related Recrystallization (Tertiary Recrystallizationtertiary recrystallization) 65
3.1.3 Dislocations 65
3.1.3.1 Dislocations at Free SurfacesDislocations at free surfaces 66
3.1.3.2 Geometrically Necessary DislocationsGeometrically necessary dislocations 66
3.2…Heat TreatmentHeat treatmentHWZZoch 67
3.2.1 Annealing Processes 67
3.2.2 Final Heat TreatmentHeat Treatment 68
3.2.2.1 Martensitic HardeningMartensitic hardening of Steels 68
3.2.2.2 Precipitation HardeningPrecipitation hardening of Aluminum Alloys 72
3.2.3 Furnace Concepts 75
3.2.3.1 QuenchingQuenching Methodsquenchingmethods: Liquid Quenchingquenching gas quenching 75
3.2.3.2 QuenchingQuenching Methodsquenchingmethods: Gas Quenchingquenching 76
3.2.3.3 Furnace Concepts: Drop-Down Tube Furnacedrop-down tube furnace 76
3.2.3.4 Furnace Concepts: Belt Furnace and Pusher Tray Furnacesfurnace concepts 79
3.3…Flow StressFlow stress 80
3.3.1 Tensile and Compression Testscompression tests 80
3.3.1.1 Tensile TestTensile tests 80
3.3.1.2 Compression TestCompression tests 81
3.3.2 Classes of Size Effectsize effects Related to Yield Strengthyield strength 83
3.3.3 Yield Strength ModelsYield strength models 83
3.3.4 Size EffectSize effects on Yield Strengthyield strength 88
3.3.5 Requirements for Testing Equipmenttesting equipment 92
3.3.6 Flow Stress AtlasFlow stress atlas 93
3.4…Endurance LimitEndurance limit 100
3.4.1 Definition 100
3.4.2 Measuring TechniqueMeasuring techniques 101
3.4.3 Influences on the Endurance LimitInfluences on the endurance limit 103
3.4.3.1 Material 103
3.4.3.2 Geometry 104
3.4.3.3 Type of Loading 105
3.4.3.4 Environment 106
3.4.4 Size EffectSize effects on the Endurance Limit 106
3.4.4.1 Density Size EffectDensity size effect 106
3.4.4.2 Shape Size EffectShape size effect 106
3.4.4.3 Microstructure Size EffectMicrostructure size effect 110
4 Bulk Metal Forming 113
4.1…Incremental Forming 114
4.1.1 Definition and Technologies 114
4.1.2 Process and Tooling 115
4.1.3 Material Effects 121
4.2…Upsetting 123
4.2.1 Basics in Upsetting 123
4.2.2 Buckling in the Upsetting Process 126
4.2.3 Formability in the Upsetting Process 128
4.2.4 Influence of Miniaturization on Friction Coefficient in the Upsetting Process 130
4.3…Cold Forging 132
4.3.1 Methods of Cold Forging 132
4.3.1.1 Fundamentals of Extrusion 133
4.3.1.2 Technology for Cold Forging of Micro Parts 135
4.3.1.3 Component Applications in the Micro Range 137
4.3.2 Materials: Process Windows and Limits 138
4.3.3 Extrusion Tools for Micro Forming 139
References 142
5 Sheet Metal Forming 144
5.1…Deep DrawingDeep Drawing 145
5.1.1 Single Step Deep Drawing Processes 145
5.1.1.1 Deep Drawing Basics 145
5.1.1.2 Influence of Miniaturization on Deep Drawing 147
5.1.1.3 Deep Drawing Without Lubricant 149
5.1.1.4 Influence of Punch Velocitypunch velocity 151
5.1.1.5 Deep Drawing of Rectangular Parts 152
5.1.2 Multi-Stage Deep Drawing 153
5.1.3 Scatter of the Punch Force 154
5.2…Stretch Drawing 155
5.2.1 Mechanical Stretch Drawing 155
5.2.2 High Speed Stretch Forming by Shock Waves 158
5.3…Bending 164
5.4…Flange Forming 170
5.5…Piercing and BlankingPiercing and Blanking 175
5.5.1 Piercing and Blanking Basics 175
5.5.2 Tools for Piercing and Blanking 176
5.5.3 Alternative Micro Piercing and Blanking Processes 179
5.5.4 Influence of Miniaturization on the Piercing and Blanking Process 181
References 183
6 Size Effect-Enabled Methods 186
6.1…Additive Sheet Generation 187
6.1.1 Thin Sheet Generation: Common Methods and Alternatives 187
6.1.2 SputteringSputtering: Principles 188
6.1.3 Morphology of Sputtered Foils 190
6.1.4 Sputtering of High Strength Aluminum Foils 192
6.1.5 Mechanical Properties of High Strength Aluminum Foils 194
6.2…Thermal Free form Heading 197
6.2.1 Basic Aspects of Thermal Free form Heading 197
6.2.2 Process Principle and Variants 198
6.2.3 Process Analysis 199
6.2.3.1 Process LimitsProcess limits 199
6.2.3.2 Adiabatic Energy ModelAdiabatic energy model 200
6.2.3.3 Influence of Laser Beam Source 201
6.2.3.4 Reproducibility of ProcessReproducibility of Process 204
6.2.3.5 Influence of Shielding Gas 204
6.2.4 Formability of Preforms Generated by Thermal Free form HeadingBrüning 206
7 Tool Making 209
7.1…Tool MaterialsTool materials 212
7.1.1 Spray FormingSpray Forming 216
7.1.2 Thermal SprayingThermal Spraying 222
7.1.3 Properties of Graded Tool Materials 224
7.1.3.1 Mechanical Properties 224
7.1.3.2 Wear Resistance 227
7.1.3.3 Corrosion ResistanceCorrosion Resistance 230
7.2…Additive Manufacturing 231
7.2.1 Basic Principles and Prospects 231
7.2.2 Design Rules for Micro Parts 240
7.2.3 Multi Material Processes 243
7.3…Laser Based Subtractive Methods 245
7.3.1 Laser MillingLaser Milling 245
7.3.1.1 Introduction and DefinitionIntroduction and Definition 245
7.3.1.2 Laser Subtracted ChipLaser Subtracted Chip 246
7.3.1.3 Method of ChoiceMethod of Choice 248
7.3.1.4 Laser Milling Via Non-Reactive Gas JetLaser Milling Via Non-Reactive Gas Jet 251
7.3.1.5 Laser Milling Via Grit BlastingLaser Milling Via Grit Blasting 254
7.3.1.6 Laser Milling Via Reactive Gas JetLaser Milling Via Reactive Gas Jet 255
7.3.1.7 Laser Milling in a Reactive Ambient GasLaser Milling in a Reactive Ambient Gas 255
7.3.1.8 Laser Milling by Intersecting BeamsLaser Milling by Intersecting Beams 256
7.3.1.9 Fracture Machining 257
7.3.2 Laser AblationLaser Ablation 258
7.3.2.1 DefinitionDefinition 258
7.3.2.2 Laser Ablation with Long PulsesLaser ablation with long pulses 258
7.3.2.3 Laser Ablation with Short PulsesLaser ablation with short pulses 263
7.3.2.4 Laser Ablation with Ultrashort PulsesLaser ablation with ultrashort pulses 264
7.3.3 Laser-Induced Chemical MachiningLaser-induced chemical machining 266
7.3.3.1 Process Fundamentals 266
7.3.3.2 Process Method 270
7.3.3.3 Achievable Structures 272
7.3.3.4 In-situ Process Monitoring 274
7.4…Cutting and Abrasive Processes 275
7.4.1 Machining Processes and Machine Tools 275
7.4.1.1 Machine Tool 276
7.4.1.2 Environment 277
7.4.1.3 Subsystems 277
7.4.1.4 CNC control 277
7.4.2 Cutting Processes 277
7.4.2.1 Cutting Tools 280
7.4.2.2 Material Removal Rate 280
7.4.2.3 Shape Accuracy and Surface Quality 282
7.4.2.4 Tribological Behavior 283
7.4.2.5 Cutting Forces 283
7.4.2.6 Tool Wear 285
7.4.3 Grinding 286
7.4.3.1 Material Removal Mechanisms 286
7.4.3.2 Grinding Tools 288
7.4.3.3 Grinding Kinematics for Mold Making 288
7.4.3.4 Surface Quality 290
7.4.3.5 Ultrasonic Assisted GrindingUltrasonic assisted grinding 290
7.4.4 Polishing 291
7.4.4.1 Abrasive Polishing 291
7.4.4.2 Laser Polishing 294
7.4.4.3 Friction PolishingFriction Polishing 295
7.5…Surface Coating 297
7.5.1 Physical Vapor deposition 297
7.5.2 Chemical Vapor Deposition 301
7.5.3 Multi-Layer Systems 303
7.5.3.1 Material Combination 305
7.5.3.2 Surface Structure 307
7.5.3.3 Lubrication 308
7.5.3.4 Material Properties 308
7.5.3.5 Layer Architecture 310
7.5.3.6 Coatability 311
References 313
8 Machines and Handling 319
8.1…PressesPresses 319
8.1.1 Classification 319
8.1.2 Work-Linked PressesWork-Linked Presses 320
8.1.3 Force-Linked PressesForce-Linked Presses 320
8.1.4 Travel-Linked PressesTravel-Linked Presses 321
8.1.5 Hybrid PressesHybrid Presses 323
8.1.6 Engineering of a PressEngineering of a Press 325
8.2…Special Purpose Machines 330
8.2.1 Design of Rotary Swaging Machines 330
8.2.2 Extensions and Modifications of Small Machines Principally for Micro Forming 331
8.2.2.1 Synchronization of Workpiece Rotation 331
8.2.2.2 Axial Workpiece Feed Device 332
8.2.2.3 Radial Feed of the Tools 332
8.2.3 Development of the Potential of Dry Processing 332
8.2.4 Modification of Tools for Micro Forming 335
8.2.4.1 Adaption of Tool Osculation 335
8.2.4.2 Coating and Structuring of the Tool Surface 336
8.2.4.3 Closure of the Gaps Between the Tools for Small Component Geometries 337
8.2.5 Design of Micro Cold Forging Machines 337
8.3…Handling of Microparts 339
8.3.1 Challenges and Principles of Micro Handling 339
8.3.2 Piece Part Handling 340
8.3.2.1 Micro Gripper 340
8.3.2.2 Feeding Systems 341
8.3.2.3 Precision Robots 343
8.3.2.4 Non Contact Piece Part HandlingHandling 343
8.3.3 Linked PartsLinked Parts Handling 345
8.3.3.1 Basic Forms of Linkages 345
8.3.3.2 Synchronization of Linked Parts 348
8.3.3.3 Strategies for the Extraction of Scrap Parts from Linked Parts 348
8.3.4 Accuracies and Tolerances in Micro Handling 349
References 350
9 Simulation Technologies 352
9.1…FEM-Simulation 354
9.1.1 Mechanical Models for Micro Metal Forming 354
9.1.2 Mathematical Foundations and Numerical Implementations 356
9.1.3 The Role of Different Scales in the Simulation of Micro Components 359
9.1.4 Multi-Scale Finite Element Methods 360
9.1.5 Computations in the Second Scale 361
9.1.6 Crystal Plasticity Methods 364
9.2…Hybrid Simulation 366
9.2.1 Stochastic Model for Textured Metals 366
9.2.2 Stochastic Two-Scale FEM 369
9.2.3 Application of the Stochastic Two-Scale Method to the Bulging Test 371
9.3…Inverse Modelling 375
9.3.1 Forward Model 376
9.3.1.1 Numerical example of the forward model 380
9.3.2 Parameter Identification Problem in Micro Cutting Operations 380
References 385
10 Quality Aspects 387
10.1…Metrology 389
10.1.1 Quality Inspection 389
10.1.2 Tactile Metrology 393
10.1.3 Optical MetrologyOptical Metrology 398
10.1.3.1 Description of Distinctive Features of Microformed Parts and Their Classification 398
10.1.3.2 Overview on Different Optical Methods for Micro Measurement 401
10.1.3.3 Testing StrategyTesting Strategy for Measuring a Micropart Using Digital HolographHolograph 405
10.1.4 Measuring Uncertainty 410
10.1.5 Quality-Oriented Process Planning 413
10.2…Closed-Loop Control 417
10.2.1 Types of Control-Loops According to the Measuring Methods 418
10.2.2 Application of Quality Controlquality control Systems in Micro Manufacturing 421
10.3…Quality-Oriented Design of Process Chains 422
10.3.1 Process Chain Design in Micro-Manufacturing 422
10.3.2 Fundamentals of Process Chain DesignProcess Chain Design 423
10.3.3 Configuration and Evaluation of Process Chains 425
10.3.4 Design Aspects of an Integrated Micro Manufacturing Process Chain 428
10.3.5 Example: Quality-Oriented Design of a Micro Deep Drawing Process Chain 430
10.3.5.1 Determining the Sample Size and Interval 431
10.3.5.2 Surface Inspection and Rectification 432
References 433
Index 437