Written by an engineer with decades of practical manufacturing experience, this new edition has been thoroughly revised and is a complete modern guide to sheet metal forming processes and die design - still the most commonly used methodology for the mass-production manufacture of aircraft, automobiles, and complex high-precision parts. Included are the "hows" and "whys" of product analysis, as well as the techniques for blanking, punching, bending, deep drawing, stretching, material economy, strip design, movement of metal during stamping, and tooling. Its focus is on simple, applicable engineering methods rather than complex numerical techniques.

Preface to the Second Edition xv

Preface to the First Edition xvi

List of Tables xviii

Introduction xxi

PART ONE THEORETICAL FUNDAMENTALS 1

Chapter ONE The Structure of Metals 3

1.1 Introduction 3

1.2 Atomic Structure 4

1.3 Bonding Between Atoms and Molecules 5

      1.3.1 Primary Bonds 5

      1.3.2 Secondary Bonds 8

1.4 The Crystal Structure of Metals 8

1.5 Deformation and Strength of Single Crystals 11

      1.5.1 Imperfections in the Crystal Structure of Metals 12

      1.5.2 Grain Size and Boundary 14

      1.5.3 Strain Hardening 15

1.6 Recovery and Recrystallization 16

Chapter TWO Mechanical Behavior of Materials 19

2.1 Introduction 19

2.2 Stress/Strain Curves 22

2.3 Ductility 24

2.4 True Stress and True Strain 25

2.5 Hardness 27

      2.5.1 Hardness Tests 27

2.6 Effect of Temperature on Material Properties 31

PART TWO MANUFACTURING PROCESESS 35

Chapter THREE Shearing Process 37

3.1 Mechanics of Shearing 37

3.2 Shearing Forces 38

      3.2.1 Shearing with Straight Parallel Cutters 38

      3.2.2 Shearing with Straight Inclined Cutters 40

      3.2.3 Shearing with Rotary Cutters 41

Chapter FOUR Blanking and Punching 43

4.1 Blanking and Punching Mechanism 43

4.2 Blanking and Punching Clearance 45

4.3 Punch Force 48

      4.3.1 Punch and Die with Parallel-Cut Edges 48

      4.3.2 Punch and Die with Bevel-Cut Edges 48

4.4 Material Economy 49

      4.4.1 Scrap Strip Layouts 50

      4.4.2 Altering the Design of the Workpiece 52

      4.4.3 Multi-Line Layout 52

      4.4.4 Utilizing Scrap from One Piece as Material for Another Piece 53

4.5 Shaving 53

      4.5.1 Shaving a Punched Workpiece 54

      4.5.2 Shaving a Blanked Workpiece 58

Chapter FIVE Bending 61

5.1 lntroducton 61

5.2 Mechanics of Bending 62

5.3 Moment of Bending 62

      5.3.1 Moment of Bending in the Elastic-Plastic Domain 65

      5.3.2 Moment of Bending in the Purely Plastic Domain 66

5.4 Bending Forces 67

      5.4.1 Force for U-Die 67

      5.4.2 Forces for a Wiping Die 69

      5.4.3 Forces for V-Die 70

      5.4.4 Curling 72

      5.4.5 Three-Roll Forming 74

5.5 Bend Radius 76

      5.5.1 Mini mum Bend Radius 76

      5.5.2 Maximum Bend Radius 78

5.6 Bend Allowance 79

5.7 Springback 83

5.8 Clearance 86

Chapter SlX Deep Drawing 87

6.1 Introduction 87

6.2 Mechani cs of Deep Drawing 89

      6.2.1 Deep Drawability 91

6.3 Forces 93

      6.3.1 First Drawi ng Operation 93

      6.3.2 Subsequent Drawing Operations 94

6.4 Blank Calculations for Rotational Symmetrical Shells 95

      6.4.1 Method of Partial Areas 95

      6.4.2 Analytical Method 97

      6.4.3 Influence of Wall Th ickness on Blank Calculations 99

      6.4.4 allowance for Trimming 101

      6.4.5 Shells with Reduced Thickness of Wall 105

6.5 Determinin g Shape of Blank for Nonsymmetrical Shells 107

      6.5.1 Rectangular Shells 107

      6.5.2 Square ShelI 111

6.6 Drawing Practice 112

      6.6.1 Defects During Deep Drawing 112

      6.6.2 Lubrication i n Draw i ng 112

Chapter SEVEN Various Forming Processes 115

7.1 Stretch Forming 115

7.2 Nosing 117

7.3 Expandi ng 121

7.4 Dimpling 124

7.5 Spi nning 126

7.6 Flex ible Die Form ing 128

      7.6.1 Guerin Process 129

      7.6.2 Verson-Wheelon Process 129

      7.6.3 Marfonn Process 130

      7.6.4 Hydrofo口ning Process 131

      7.6.5 Force in Die Forming 132

PART THREE DIE DESIGN 135

Chapter EIGHT Basic Die Classifications and Components 137

8.1 Die Classifications 137

      8.1.1 Die Classifications Depending on the Production Quantity of Parts 137

      8.1.2 Die Classifications According to Number of Stations 138

      8.1.3 Die Classifications According to Manufacturing Processes 139

8.2 Basic Die Components 140

Chapter NINE Blanking and Punching Dies 145

9.1 Introduction 145

9.2 Die Blocks 146

      9.2.1 Die Opening Profile 146

      9.2.2 Fastening to the Die Shoe 147

      9.2.3 Sectioned Die 148

      9.2.4 Calculation of Die Block Dimensions 150

9.3 Punches 1 52

      9.3.1 Punch Face Geometry 153

      9.3.2 Methods for Assembling Punches 153

      9.3.3 Punch Calculations 155

9.4 Stripper Plates 157

      9.4.1 Stripper Force 157

      9.4.2 Stripper Design 158

9.5 Die Components for Guiding and Stopping 162

      9.5.1 Stock Guides and Guide Rails 162

      9.5.2 Die Stops and French Notch Punch 164

      9.5.3 Positioning the Individual Blank 166

      9.5.4 Pilots 167

9.6 Center of Die Pressure 167

9.7 Examples of Cutting Die Designs 169

Chapter TEN Bending Dies 173

10.1 Introduction 173

10.2 Simple Die Designs 173

      10.2.1 U-Profile Bend Dies 174

      10.2.2 V-Profile Bend Dies 175

      10.2.3 Universal Bending Dies 177

10.3 Dies of Complex Design 178

      10.3.1 Closing Profile Dies 178

      10.3.2 Special Bendi ng Dies 179

      10.3.3 Curling and Hinge Dies 182

      10.3.4 Tube-Forming Dies 182

      10.3.5 Multiple-Bend Dies 184

      10.3.6 Combi nation Dies 185

      10.3.7 Progressive Dies 185

Chapter ELEVEN Deep Drawing Dies 189

11.1 Introduction 189

11.2 Draw Rings 190

      11.2.1 Draw Ring with Corner Radius 190

      11.2.2 Draw Ring with Conical Profile 192

      11.3 Clearances and Tolerances 194

      11.3.1 Calculation of the Dimensions of the Punch and Die 194

11.4 Blank Holders 197

      11.4.1 Blank Holder Pressure 198

      11.4.2 Blank Holder Force 198

      11.4.3 Draw Beads 200

11.5 Single-Operation Dies 20 1

11.6 Multi-Operation Dies 203

11.7 Progressive Drawing Dies 204

11.8 Drawing Dies for Spherical and Parabolic Shape Shells 205

11.9 Ironing Dies 207

Chapter TWELVE Various Forming Dies 209

12.1 Nosing Dies 209

12.2 Expanding and Bulging Dies 213

      12.2.1 Expanding Dies 213

      12.2.2 Bulging Dies 213

      12.3 Flanging Dies 215

Chapter TIDRTEEN Tool and Die Materials 217

13.1 introduction 217

13.2 Carbon and Alloy Steels 218

      13.2.1 Designations for Carbon and Alloy Steels 218

      13.2.2 Effects of Various Alloy Elements in Steels 219

      13.2.3 Carbon Steels 219

      13.2.4 Alloy Steels 220

      13.2.5 Machinability of Steels 220

      13.2.6 Mechanical Properties of Steels 220

      13.2.7 Applications of Carbon and Alloy Steels 222

13.3 Tool and Die Steels 222

      13.3.1 Designation and Classification of Tool and Die Steels 222

      13.3.2 Cold Work Tool and Die Steels 223

13.4 Nonferrous Metals 225

13.5 Non-Metallic Materials 225

Chapter FOURTEEN Quick Die-Change Systems and Die Design 227

14.1 Introduction 227

      14.1.1 Quick Die Change Benefits 228

14.2 Quick Die-change System Configuration 229

      14.2.1 Die Clamping Systems 229

      14.2.2 Die Transfer, Transport and Positioning Systems 235

      14.2.3 Other Components of Quick Die-Change Systems 239

14.3 Implementation of Quick Die-Change Systems 241

      14.3.1 Die Design for Quick Die-Change Systems 242

      14.3.2 Selection of Die Transfer Methods 243

      14.3.3 Selection of Die Clamping Systems 243

      14.3.4 Selection of Die Lifter System 244

      14.3.5 Selection of Support Equipment 245

      14.3.6 Safety Circuits and Evaluation 245

Appendix 1 Blank Diameter of Drawn Shells 247

Appendix 2 Metric System Tolerances on Linear Dimensions 252

Appendix 3 Miscellaneous Information 262

Appendix 4 Technical Specification of the Helical and Belleville Springs 273

Glossary 281

Bibliography 291

Index 293

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