An Advanced Treatise On Fixture Design And Planning

by Nee, A. Y. C.; Tao, Z. J.; Kumar, A. Senthil

• ISBN13: 9789812560599
• ISBN10: 9812560599
• Format: Hardcover
• Copyright: 2004-12-28
• Publisher: World Scientific Pub Co Inc

Summary

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.

Table of Contents

Chapter 1 Introduction to Fixture Design
1.1 Introduction	1	(8)
1.1.1 Elements of Fixtures	1	(2)
1.1.2 Importance of Fixtures in Manufacturing	3	(1)
1.1.3 General Requirements of a Fixture	4	(2)
1.1.4 Fixture Design Fundamentals	6	(3)
1.1.4.1 Fixture Design	6	(2)
1.1.4.2 Fixture Design Criteria	8	(1)
1.1.4.3 Fixture Design Procedure	8	(1)
1.2 Locating Principles	9	(1)
1.2.1 Introduction	9	(1)
1.2.2 Restrictions on the Degrees of Freedom of a Workpiece	9	(1)
1.3 Clamping Principles	10	(3)
1.3.1 Introduction	10	(1)
1.3.2 Basic Principles of Clamping	11	(2)
1.3.2.1 Orientation of Locators vis-à-vis Clamping Force	11	(1)
1.3.2.2 Effect of External Force on the Clamping Action	11	(1)
1.3.2.3 Types of Clamps	12	(1)
1.4 Automation in Fixture Design	13	(5)
1.4.1 The Need for More Flexible Fixtures	13	(1)
1.4.2 Computer-aided Fixture Design Research	14	(3)
1.4.2.1 Geometric Analysis	14	(1)
1.4.2.2 Kinematic Analysis	15	(1)
1.4.2.3 Force Analysis	16	(1)
1.4.2.4 Deformation Analysis	17	(1)
1.4.3 Novel Clamping System Design	17	(1)
1.5 Summary	18	(1)
1.6 Bibliography	18	(3)
Chapter 2 Computer Aided Conceptual Fixture Design
2.1 Introduction	21	(2)
2.2 Integrated Prototype System	23	(4)
2.2.1 Interactive Fixture Design System	23	(4)
2.2.2 Automated Fixture Design	27	(1)
2.3 Automated Fixturing Points Determination	27	(7)
2.3.1 Generation of Candidate Supporting Points	29	(1)
2.3.2 Generation of Candidate Locating Points	30	(1)
2.3.3 Selection of Supporting Points	31	(1)
2.3.4 Selection of Locating Points	32	(1)
2.3.5 Selection of Clamping Points	33	(1)
2.4 Machining Interference Detection	34	(6)
2.4.1 Cutter Location Source File	34	(1)
2.4.2 Formation of Motion Silhouettes	35	(3)
2.4.3 Generation of Cutter Swept Solid	38	(1)
2.4.4 Collision Detection by Static Interference Check	39	(1)
2.5 Illustrative Example	40	(4)
2.6 Summary	44	(1)
2.7 Bibliography	44	(3)
Chapter 3 Fixture Clamping Layout Synthesis
3.1 Introduction	47	(1)
3.2 Importance of Analytical Approach	48	(1)
3.3 Observation	49	(1)
3.3.1 Clamping Equilibrium	49	(1)
3.3.2 Force Closure	49	(1)
3.4 Contact Force Model	49	(5)
3.4.1 Conservative Representation and Accuracy	52	(1)
3.4.2 Contacting Wrench	53	(1)
3.5 Gravitational Force	54	(1)
3.6 Force Closure Condition	54	(3)
3.7 Clamping Equilibrium	57	(2)
3.7.1 Grasping vs. Fixturing	57	(1)
3.7.2 Condition for Clamping Equilibrium	57	(2)
3.8 Verification of Force Closure for 2-D Workpiece	59	(3)
3.9 Criteria for Clamping Layout Reasoning	62	(2)
3.10 Automatic Generation of Clamping Points and Sequence	64	(2)
3.10.1 Consideration of Physical Constraints	66	(1)
3.11 Algorithm Implementation	66	(1)
3.12 Case Studies	67	(10)
3.12.1 Planar Fixturing Problems	67	(6)
3.12.1.1 Verification of Force Closure	68	(1)
3.12.1.2 Best Clamping Points and Positive Clamping Sequence	68	(5)
3.12.2 Spatial Fixturing Problems	73	(10)
3.12.2.1 Prismatic Workpiece	73	(3)
3.12.2.2 Engineering Workpiece	76	(1)
3.13 Summary	77	(3)
3.14 Bibliography	80	(3)
Chapter 4 Optimisation of Dynamic Clamping Forces for a Fixture
4.1 Introduction	83	(1)
4.2 Direct Computation Approach	83	(6)
4.2.1 Minimal Clamping Force for Frictionless Fixturing	83	(2)
4.2.2 An Illustrating Example	85	(1)
4.2.3 Minimal Clamping Force for Frictional Fixturing	86	(2)
4.2.4 An Illustrating Example	88	(1)
4.3 Generic Model for Clamping Force Optimisation	89	(5)
4.3.1 Complete Representation of Contact Force	89	(2)
4.3.2 Positive Location Constraint	91	(1)
4.3.3 External Load	92	(1)
4.3.4 Workpiece Static Equilibrium	93	(1)
4.4 Optimal Clamping Force Algorithm	94	(5)
4.4.1 Minimum Clamping	94	(2)
4.4.2 Safety Consideration	96	(1)
4.4.3 Maximum Clamping	96	(2)
4.4.4 Polygonal Contacts	98	(1)
4.5 Algorithm Implementation	99	(2)
4.6 Case Studies	101	(6)
4.6.1 Planar Fixturing	101	(2)
4.6.2 Spatial Fixturing	103	(4)
4.7 Summary	107	(1)
4.8 Bibliography	108	(3)
Chapter 5 Workpiece-Fixture Interaction
5.1 IIntroduction	111	(1)
5.2 Experimental Investigation	111	(13)
5.2.1 Sensor-integrated Fixture System	112	(4)
5.2.1.1 Forces within a Fixture	112	(1)
5.2.1.2 Sensor Embedded Locator	113	(1)
5.2.1.3 Data Acquisition for Reaction Forces	114	(1)
5.2.1.4 Physical Configuration	115	(1)
5.2.2 Experimentation	116	(4)
5.2.2.1 Machining Operation	116	(2)
5.2.2.2 Top Clamping	118	(1)
5.2.2.3 Side Clamping	119	(1)
5.2.3 Discussion on Reaction Forces	120	(7)
5.2.3.1 Top Clamping	122	(1)
5.2.3.2 Side Clamping	122	(1)
5.2.3.3 Spectral Analysis of Reaction Forces	123	(1)
5.3 Finite Element Analysis	124	(10)
5.3.1 Contact Force/Deflection Relationships	127	(1)
5.3.2 Contact Approach	128	(1)
5.3.3 FEM Model and Solution	129	(1)
5.3.4 Model Validation	129	(2)
5.3.4.1 Comparison of Reaction Forces	130	(1)
5.3.5 Deformation under Dynamic Clamping	131	(3)
5.4 Summary	134	(1)
5.5 Bibliography	135	(4)
Chapter 6 An Intelligent Fixturing System
6.1 Introduction	139	(1)
6.2 Architecture of an Intelligent Fixturing System	140	(8)
6.2.1 System Functions: From Viable Design to Optimal Execution	140	(4)
6.2.1.1 Optimal Design Procedure	142	(2)
6.2.2 "Live" Fixture for Precision Machining	144	(4)
6.2.2.1 Clamping Sub-tasks	144	(1)
6.2.2.2 System Overview	144	(4)
6.3 Tool Path Compensation	148	(12)
6.3.1 Determination of Workpiece Displacement	148	(3)
6.3.2 Workpiece Displacement by Experimental Measurement	151	(4)
6.3.3 Tool Path Compensation	155	(5)
6.3.3.1 Linear Compensation	155	(2)
6.3.3.2 Angular Compensation	157	(3)
6.4 Dynamic Clamping Actuator	160	(2)
6.4.1 Fixturing Error Control Strategy	160	(1)
6.4.2 Need for Dynamic Clamping Force	160	(1)
6.4.3 Dynamic Clamping Actuator	161	(1)
6.4.3.1 Sensor Integration	161	(1)
6.4.3.2 Digital Interfacing	162	(1)
6.4.3.3 Clamping Force Control	162	(1)
6.4.3.4 Clamping Task Programmability	162	(1)
6.5 Clamping Force Control Strategy	162	(6)
6.5.1 DC Motor Servo Controller	164	(1)
6.5.2 System Identification of Process	165	(1)
6.5.3 Generalised Minimum Variance Model	166	(2)
6.6 Experimental Facility	168	(1)
6.7 Validation of Dynamic Clamping	169	(6)
6.7.1 Validating Experimentation and Discussions	171	(2)
6.7.2 Workpiece Stability under Dynamic Clamping	173	(2)
6.8 Impact of Intelligent Fixturing System	175	(9)
6.8.1 Typical Dynamic Workholding Procedure	175	(1)
6.8.2 Experiments on Thin-walled Workpieces	176	(2)
6.8.3 Geometric Accuracy Improvement	178	(5)
6.8.3.1 Comparison with Fixed Clamping	179	(4)
6.8.4 Finished Surface Quality	183	(1)
6.8.5 Process Cycle Time	184	(1)
6.9 Summary	184	(1)
6.10 Bibliography	185	(2)
Chapter 7 A Database Management System for Modular Fixtures
7.1 Introduction	187	(1)
7.2 System Overview	187	(2)
7.2.1 Enquiry Module	188	(1)
7.2.2 Element Database Module	188	(1)
7.2.3 Job Module	188	(1)
7.2.4 Schedule Module	188	(1)
7.2.5 Simulation Module	189	(1)
7.3 System Implementation	189	(8)
7.3.1 Data Storage Capability	190	(2)
7.3.2 Data Access Capability	192	(1)
7.3.3 Data Sorting Capability	193	(1)
7.3.4 Simulation Capability	194	(1)
7.3.5 Data Extraction Capability	195	(2)
7.3.5.1 Minimum Inventory Level	195	(1)
7.3.5.2 Useful Life Span of Elements Expended	195	(1)
7.3.5.3 Number of Elements Used Per Month	196	(1)
7.3.5.4 Weight of Fixture Design (Without Workpiece)	196	(1)
7.3.5.5 Cost of Fixture Design (Without Workpiece)	197	(1)
7.3.5.6 Percentage of Each of the Category of Element in a Job	197	(1)
7.4 Evaluation of the FE_DBMS	197	(3)
7.4.1 Inventory Enquiry	197	(1)
7.4.2 Cost Enquiry	198	(1)
7.4.3 Weight Enquiry	198	(1)
7.4.4 Monthly Enquiry	199	(1)
7.4.5 Purchasing Policy	199	(1)
7.5 Summary	200	(1)
7.6 Bibliography	200	(1)
Chapter 8 An Internet-Enabled Smart Interactive Fixture Design System
8.1 Introduction	201	(2)
8.1.1 Standalone Systems	201	(1)
8.1.2 Internet-Enabled System	202	(1)
8.1.3 Java and Java3D	202	(1)
8.2 System Architecture	203	(7)
8.2.1 Server Side	203	(1)
8.2.2 Client Side	203	(3)
8.2.3 XML Schemas	206	(2)
8.2.3.1 Fixture Design XML	206	(1)
8.2.3.2 Facet Data XML	206	(1)
8.2.3.3 Product Data XML	206	(2)
8.2.4 System Application Process	208	(2)
8.3 System Structure	210	(10)
8.3.1 Application Process	210	(3)
8.3.2 Limitations	213	(1)
8.3.3 Storage Structure	213	(1)
8.3.4 Retrieval Structure	214	(2)
8.3.5 Changing a Design	216	(5)
8.3.5.1 Object Delete Function	216	(2)
8.3.5.2 Design Process for Existing System	218	(2)
8.4 System Architecture	220	(10)
8.4.1 Support Pin Rules	221	(1)
8.4.1.1 Support Rule Implementation Process	222	(1)
8.4.2 Locator Rules	222	(3)
8.4.2.1 Locator Rule Implementation Process	225	(1)
8.4.3 Clamp Rules	225	(3)
8.4.3.1 Side Clamp Rule Implementation Process	225	(3)
8.4.4 Limitations of SIFD Module	228	(2)
8.5 An Illustrative Case Study	230	(10)
8.6 Summary	240	(1)
8.7 Bibliography	240	(3)
Index	243	(4)
List of Authors	247