| Preface IX 1. Introduction 1 Definition, purpose and advantages 2 Application 5 Type of jigs 7 Type of fixtures 11 Design principles of jig and fixture: 16 2. Preliminary Analysis and Fixture Planning 21 Introduction 21 The initial design concept 22 Blue prints and specifications 28 Industrial laser cutting 30 Drilling jigs: 31 Chips 34 3. The Fixture Design Procedure 39 Introduction 39 Steps in the fixture design process 39 Locating and degree of freedom 40 Using the clamping elements 41 Providing support 42 Cutter guidance 42 Steels,not specified 43 Aluminium and magnesium 46 Castings 48 Sintered carbides 50 Plastics 50 Other non metallic metals 51 4. Locating Principles 54 Introduction 54 Locating principles, flat surfaces 54 Nesting 64 The 3-2-1 principles 68 The 4-2-1 principles error possibilities 69 5. Preparation of Locating 72 Introduction 72 Locating unmachined surfaces 72 Castings 73 Filling 73 Forgings 75 Weldments 78 6. Design of Locating Components 84 Introduction 84 Pins 84 General requirements 86 Forms of location 87 Analyzing machining forces 90 7. Loading and Unloading 93 Introduction 93 Symmetry considerations 93 Foolproofing 95 Removal problems 95 Burred Parts 96 Ejectors 96 Loading of large and heavy parts 97 Receivers, sliding or rotating 97 8. Chip Problems 100 Introduction 100 Types of chips 100 Burr formation 103 Chip removal 103 Thermal changes in shape of the workpiece 103 Shields and seals 104 9. Centralizers 108 Introduction 108 Definition 108 Advantages 110 Centralizers and locators 110 Classifications 113 Centering by v block 114 10. Clamping Elements 117 Introduction 117 Classification 118 Selecting clamp size and force 125 The mechanics of wedges 127 The mechanics of screws 127 Spiral cams 129 Mechanics of toggle clamps 129 Eccentric cams 131 Jackscrew 131 Clamping manderel mounted work 132 Angular clamp 132 Swnging leaves 133 The use of adapters 134 Mechanical chucks 134 Electrostatic chucks 134 Vacuum clamping 135 11. Equalizers 142 Introduction 142 Graphic equalizers 143 Parametric equalizers 144 Linear-phase equalizers 145 Dynamic equalizers 145 The floating principle 146 Double movement clamps 146 Multiple clamping 146 Hydraulic equilizers 147 Plastic fillings 151 12. Supporting Elements 156 Introduction 156 Screw type supports 156 Support types 158 Reactions 158 Roller supports 158 Pinned supports 159 Pinned connections 159 Fixed supports 160 Fixed connections 160 Simple supports 160 13. Cutter Guides 163 Introduction 163 Definitions and principal types 163 Essentials of milling fixtures: 170 14. Drill Bushings 174 Introduction 174 Definitions 174 Types 174 Standard bushings 175 Mounting of bushings –press bushings 175 Installation of bushings –renewable bushings 176 Drils with attached bushings 180 Empirical formulas for design of bushings 180 Materials for bushings 182 15. Design of Fixture Bodies 188 Drawings 188 Design consideration in fixtures 188 U – lug design: 190 T – slots and keys: 190 Drill jigs 190 Fixture clamping 193 Fixture clamps 193 Concentric fixture clamps 194 Alingement 194 Key advantages and features 194 Dowel pin applications 196 Assembly screws 197 Built up fixtures 198 Experimental design 198 Results and analysis 199 Signal-to-noise ratio graph of surface roughness 200 Developing a welding fixture 202 16. Design Studies I-Milling Fixtures 212 Introduction 212 Ypical milling fixture 213 Contour and profile milling fixture 214 Fixture for n/c milling 227 17. Design Studies II Miscellaneous Fixtures 230 Introduction 230 Lathe fixture in general 230 Chuck fixtures 231 Face plate fixture 232 Boring fixtures 233 Angle plate fixture 233 Automotive grinding fixtures 234 Broaching fixtures 235 Fixture for internal broaching 236 Aircraft tooling 238 18. Universal and Automatic Fixtures 246 Introduction 246 Definition of universal 247 Universal drill jigs 247 Universal fixtures 249 Automatic fixtures 251 Fixture for transfer machines and n/c machine tools 252 19. Economics 262 Introduction 262 Estimate of profit 262 Estimation of fixture cost 263 Bibliography 266 Index 268 |
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