An Advanced Treatise On Fixture Design And Planning (Series on Manufacturing Systems and Technology)

"Fixtures are an essential part of manufacturing production. This book covers computer-aided fixture design, fixture clamping synthesis and optimisation, workpiece-fixture interaction, intelligent fixture designed to integrate with processing equipment or machine tools so as to improve productivity and product quality, Internet-enabled fixture design and modular fixture database management. These are the emerging issues central to the development of computer-integrated manufacturing. Covering the established knowledge of fixture design automation and the niche areas of fixture system integration and Internet-enabled design, the book would be a prevalent reference for academics, manufacturing & industrial engineers, and a valuable text for engineering graduate students. " Preface 8 Acknowledgements 9 Table of Contents 10 Chapter 1 Introduction to Fixture Design 16 1.1 Introduction 16 1.1.1 Elements of Fixtures 16 1.1.2 Importance of Fixtures in Manufacturing 18 1.1.3 General Requirements of a Fixture 19 1.1.4 Fixture Design Fundamentals 21 1.2 Locating Principles 24 1.2.1 Introduction 24 1.2.2 Restrictions on the Degrees of Freedom of a Workpiece 24 1.3 Clamping Principles 25 1.3.1 Introduction 25 1.3.2 Basic Principles of Clamping 26 1.4 Automation in Fixture Design 28 1.4.1 The Need for More Flexible Fixtures 28 1.4.2 Computer-aided Fixture Design Research 29 1.4.3 Novel Clamping System Design 32 1.5 Summary 33 1.6 Bibliography 33 Chapter 2 Computer Aided Conceptual Fixture Design 36 2.1 Introduction 36 2.2 Integrated Prototype System 38 2.2.1 Interactive Fixture Design System 38 2.2.2 Automated Fixture Design 42 2.3 Automated Fixturing Points Determination 42 2.3.1 Generation of Candidate Supporting Points 44 2.3.2 Generation of Candidate Locating Points 45 2.3.3 Selection of Supporting Points 46 2.3.4 Selection of Locating Points 47 2.3.5 Selection of Clamping Points 48 2.4 Machining Interference Detection 49 2.4.1 Cutter Location Source File 49 2.4.2 Formation of Motion Silhouettes 50 2.4.3 Generation of Cutter Swept Solid 53 2.4.4 Collision Detection by Static Interference Check 54 2.5 Illustrative Example 55 2.6 Summary 59 2.7 Bibliography 59 Chapter 3 Fixture Clamping Layout Synthesis 62 3.1 Introduction 62 3.2 Importance of Analytical Approach 63 3.3 Observation 64 3.3.1 Clamping Equilibrium 64 3.3.2 Force Closure 64 3.4 Contact Force Model 64 3.4.1 Conservative Representation and Accuracy 67 3.4.2 Contacting Wrench 68 3.5 Gravitational Force 69 3.6 Force Closure Condition 69 3.7 Clamping Equilibrium 72 3.7.1 Grasping vs. Fixturing 72 3.7.2 Condition for Clamping Equilibrium 72 3.8 Verification of Force Closure for 2-D Workpiece 74 3.9 Criteria for Clamping Layout Reasoning 77 3.10 Automatic Generation of Clamping Points and Sequence 79 3.10.1 Consideration of Physical Constraints 81 3.11 Algorithm Implementation 81 3.12 Case Studies 82 3.12.1 Planar Fixturing Problems 82 3.12.2 Spatial Fixturing Problems 88 3.13 Summary 92 3.14 Bibliography 95 Chapter 4 Optimisation of Dynamic Clamping Forces for a Fixture 98 4.1 Introduction 98 4.2 Direct Computation Approach 98 4.2.1 Minimal Clamping Force for Frictionless Fixturing 98 4.2.2 An Illustrating Example 100 4.2.3 Minimal Clamping Force for Frictional Fixturing 101 4.2.4 An Illustrating Example 103 4.3 Generic Model for Clamping Force Optimisation 104 4.3.1 Complete Representation of Contact Force 104 4.3.2 Positive Location Constraint 106 4.3.3 External Load 107 4.3.4 Workpiece Static Equilibrium 108 4.4 Optimal Clamping Force Algorithm 109 4.4.1 Minimum Clamping 109 4.4.2 Safety Consideration 111 4.4.3 Maximum Clamping 111 4.4.4 Polygonal Contacts 113 4.5 Algorithm Implementation 114 4.6 Case Studies 116 4.6.1 Planar Fixturing 116 4.6.2 Spatial Fixturing 118 4.7 Summary 122 4.8 Bibliography 123 Chapter 5 Workpiece-Fixture Interaction 126 5.1 Introduction 126 5.2 Experimental Investigation 126 5.2.1 Sensor-integrated Fixture System 127 5.2.2 Experimentation 131 5.2.3 Discussion on Reaction Forces 135 5.3 Finite Element Analysis 139 5.3.1 Contact Force/Deflection Relationships 142 5.3.2 Contact Approach 143 5.3.3 FEM Model and Solution 144 5.3.4 Model Validation 144 5.3.5 Deformation under Dynamic Clamping 146 5.4 Summary 149 5.5 Bibliography 150 Chapter 6 An Intelligent Fixturing System 154 6.1 Introduction 154 6.2 Architecture of an Intelligent Fixturing System 155 6.2.1 System Functions: From Viable Design to Optimal Execution 155 6.2.2 “Live” Fixture for Precision Machining 159 6.3 Tool Path Compensation 163 6.3.1 Determination of Workpiece Displacement 163 6.3.2 Workpiece Displacement by Experimental Measurement 166 6.3.3 Tool Path Compensation 170 6.4 Dynamic Clamping Actuator 175 6.4.1 Fixturing Error Control Strategy 175 6.4.2 Need for Dynamic Clamping Force 175 6.4.3 Dynamic Clamping Actuator 176 6.5 Clamping Force Control Strategy 177 6.5.1 DC Motor Servo Controller 179 6.5.2 System Identification of Process 180 6.5.3 Generalised Minimum Variance Model 181 6.6 Experimental Facility 183 6.7 Validation of Dynamic Clamping 184 6.7.1 Validating Experimentation and Discussions 186 6.7.2 Workpiece Stability under Dynamic Clamping 188 6.8 Impact of Intelligent Fixturing System 190 6.8.1 Typical Dynamic Workholding Procedure 190 6.8.2 Experiments on Thin-walled Workpieces 191 6.8.3 Geometric Accuracy Improvement 193 6.8.4 Finished Surface Quality 198 6.8.5 Process Cycle Time 199 6.9 Summary 199 6.10 Bibliography 200 Chapter 7 A Database Management System for Modular Fixtures 202 7.1 Introduction 202 7.2 System Overview 202 7.2.1 Enquiry Module 203 7.2.2 Element Database Module 203 7.2.3 Job Module 203 7.2.4 Schedule Module 203 7.2.5 Simulation Module 204 7.3 System Implementation 204 7.3.1 Data Storage Capability 205 7.3.2 Data Access Capability 207 7.3.3 Data Sorting Capability 208 7.3.4 Simulation Capability 209 7.3.5 Data Extraction Capability 210 7.4 Evaluation of the FE_DBMS 212 7.4.1 Inventory Enquiry 212 7.4.2 Cost Enquiry 213 7.4.3 Weight Enquiry 213 7.4.4 Monthly Enquiry 214 7.4.5 Purchasing Policy 214 7.5 Summary 215 7.6 Bibliography 215 Chapter 8 An Internet-Enabled Smart Interactive Fixture Design System 216 8.1 Introduction 216 8.1.1 Standalone Systems 216 8.1.2 Internet-Enabled System 217 8.1.3 Java and Java3D 217 8.2 System Architecture 218 8.2.1 Server Side 218 8.2.2 Client Side 218 8.2.3 XML Schemas 221 8.2.4 System Application Process 223 8.3 System Structure 225 8.3.1 Application Process 225 8.3.2 Limitations 228 8.3.3 Storage Structure 228 8.3.4 Retrieval Structure 229 8.3.5 Changing a Design 231 8.4 System Architecture 235 8.4.1 Support Pin Rules 236 8.4.2 Locator Rules 237 8.4.3 Clamp Rules 240 8.4.4 Limitations of SIFD Module 243 8.5 An Illustrative Case Study 245 8.6 Summary 255 8.7 Bibliography 255 Index 258 A 258 C 258 D 258 F 259 G 259 H 259 I 260 J 260 K 260 L 260 M 260 N 260 P 260 Q 260 R 260 S 260 T 261 U 261 W 261 X 261 List of Authors 262 Preface......Page 8 Acknowledgements......Page 9 Table of Contents......Page 10 1.1.1 Elements of Fixtures......Page 16 1.1.2 Importance of Fixtures in Manufacturing......Page 18 1.1.3 General Requirements of a Fixture......Page 19 1.1.4 Fixture Design Fundamentals......Page 21 1.2.2 Restrictions on the Degrees of Freedom of a Workpiece......Page 24 1.3.1 Introduction......Page 25 1.3.2 Basic Principles of Clamping......Page 26 1.4.1 The Need for More Flexible Fixtures......Page 28 1.4.2 Computer-aided Fixture Design Research......Page 29 1.4.3 Novel Clamping System Design......Page 32 1.6 Bibliography......Page 33 2.1 Introduction......Page 36 2.2.1 Interactive Fixture Design System......Page 38 2.3 Automated Fixturing Points Determination......Page 42 2.3.1 Generation of Candidate Supporting Points......Page 44 2.3.2 Generation of Candidate Locating Points......Page 45 2.3.3 Selection of Supporting Points......Page 46 2.3.4 Selection of Locating Points......Page 47 2.3.5 Selection of Clamping Points......Page 48 2.4.1 Cutter Location Source File......Page 49 2.4.2 Formation of Motion Silhouettes......Page 50 2.4.3 Generation of Cutter Swept Solid......Page 53 2.4.4 Collision Detection by Static Interference Check......Page 54 2.5 Illustrative Example......Page 55 2.7 Bibliography......Page 59 3.1 Introduction......Page 62 3.2 Importance of Analytical Approach......Page 63 3.4 Contact Force Model......Page 64 3.4.1 Conservative Representation and Accuracy......Page 67 3.4.2 Contacting Wrench......Page 68 3.6 Force Closure Condition......Page 69 3.7.2 Condition for Clamping Equilibrium......Page 72 3.8 Verification of Force Closure for 2-D Workpiece......Page 74 3.9 Criteria for Clamping Layout Reasoning......Page 77 3.10 Automatic Generation of Clamping Points and Sequence......Page 79 3.11 Algorithm Implementation......Page 81 3.12.1 Planar Fixturing Problems......Page 82 3.12.2 Spatial Fixturing Problems......Page 88 3.13 Summary......Page 92 3.14 Bibliography......Page 95 4.2.1 Minimal Clamping Force for Frictionless Fixturing......Page 98 4.2.2 An Illustrating Example......Page 100 4.2.3 Minimal Clamping Force for Frictional Fixturing......Page 101 4.2.4 An Illustrating Example......Page 103 4.3.1 Complete Representation of Contact Force......Page 104 4.3.2 Positive Location Constraint......Page 106 4.3.3 External Load......Page 107 4.3.4 Workpiece Static Equilibrium......Page 108 4.4.1 Minimum Clamping......Page 109 4.4.3 Maximum Clamping......Page 111 4.4.4 Polygonal Contacts......Page 113 4.5 Algorithm Implementation......Page 114 4.6.1 Planar Fixturing......Page 116 4.6.2 Spatial Fixturing......Page 118 4.7 Summary......Page 122 4.8 Bibliography......Page 123 5.2 Experimental Investigation......Page 126 5.2.1 Sensor-integrated Fixture System......Page 127 5.2.2 Experimentation......Page 131 5.2.3 Discussion on Reaction Forces......Page 135 5.3 Finite Element Analysis......Page 139 5.3.1 Contact Force/Deflection Relationships......Page 142 5.3.2 Contact Approach......Page 143 5.3.4 Model Validation......Page 144 5.3.5 Deformation under Dynamic Clamping......Page 146 5.4 Summary......Page 149 5.5 Bibliography......Page 150 6.1 Introduction......Page 154 6.2.1 System Functions: From Viable Design to Optimal Execution......Page 155 6.2.2 “Live” Fixture for Precision Machining......Page 159 6.3.1 Determination of Workpiece Displacement......Page 163 6.3.2 Workpiece Displacement by Experimental Measurement......Page 166 6.3.3 Tool Path Compensation......Page 170 6.4.2 Need for Dynamic Clamping Force......Page 175 6.4.3 Dynamic Clamping Actuator......Page 176 6.5 Clamping Force Control Strategy......Page 177 6.5.1 DC Motor Servo Controller......Page 179 6.5.2 System Identification of Process......Page 180 6.5.3 Generalised Minimum Variance Model......Page 181 6.6 Experimental Facility......Page 183 6.7 Validation of Dynamic Clamping......Page 184 6.7.1 Validating Experimentation and Discussions......Page 186 6.7.2 Workpiece Stability under Dynamic Clamping......Page 188 6.8.1 Typical Dynamic Workholding Procedure......Page 190 6.8.2 Experiments on Thin-walled Workpieces......Page 191 6.8.3 Geometric Accuracy Improvement......Page 193 6.8.4 Finished Surface Quality......Page 198 6.9 Summary......Page 199 6.10 Bibliography......Page 200 7.2 System Overview......Page 202 7.2.4 Schedule Module......Page 203 7.3 System Implementation......Page 204 7.3.1 Data Storage Capability......Page 205 7.3.2 Data Access Capability......Page 207 7.3.3 Data Sorting Capability......Page 208 7.3.4 Simulation Capability......Page 209 7.3.5 Data Extraction Capability......Page 210 7.4.1 Inventory Enquiry......Page 212 7.4.3 Weight Enquiry......Page 213 7.4.5 Purchasing Policy......Page 214 7.6 Bibliography......Page 215 8.1.1 Standalone Systems......Page 216 8.1.3 Java and Java3D......Page 217 8.2.2 Client Side......Page 218 8.2.3 XML Schemas......Page 221 8.2.4 System Application Process......Page 223 8.3.1 Application Process......Page 225 8.3.3 Storage Structure......Page 228 8.3.4 Retrieval Structure......Page 229 8.3.5 Changing a Design......Page 231 8.4 System Architecture......Page 235 8.4.1 Support Pin Rules......Page 236 8.4.2 Locator Rules......Page 237 8.4.3 Clamp Rules......Page 240 8.4.4 Limitations of SIFD Module......Page 243 8.5 An Illustrative Case Study......Page 245 8.7 Bibliography......Page 255 D......Page 258 H......Page 259 S......Page 260 X......Page 261 List of Authors......Page 262 "This book covers computer-aided fixture design, fixture clamping synthesis and optimisation, workpiece-fixture interaction, intelligent fixture designed to integrate with processing equipment or machine tools so as to improve productivity and product quality, Internet-enabled fixture design and modular fixture database management. These are the emerging issues central to the development of computer-integrated manufacturing." "Covering the established knowledge of fixture design automation and the niche areas of fixture system integration and Internet-enabled design, the book would be a prevalent reference for academics, manufacturing & industrial engineers, and a valuable text for engineering graduate students."--BOOK JACKET