Fixtures are crucial to new manufacturing techniques and largely dictate the level of flexibility a manufacturing system can achieve. Advanced Fixture Design for FMS provides a systematic basis for the selection and design of fixturing systems. It gives a review of the current state of the art of flexible and reconfigurable fixturing systems. Recent developments in design methodology using CAD are analysed in depth. Fixture design is seen as an inseparable part of process planning. The primary objective of a fixture system is to ensure that the part being manufactured can be made consistently within the tolerance specified in the design. A new method of tolerance analysis is used to check the suitability of location surfaces and the sequence of operations and is explained in detail.

Inhalt

1 Fixtures and flexible manufacturing systems.- 1.1 Introduction.- 1.2 AMT and fixtures.- 1.2.1 Fixture design and rate of return on investment.- 1.2.2 Fixture design and production leadtime.- 1.3 Fixture strategies for FMS.- 1.4 References.- 2 Fixture design fundamentals.- 2.1 Introduction.- 2.2 Definitions.- 2.3 Fixture design.- 2.4 Design outcomes.- 2.4.1 Fixture plan.- 2.4.2 Fixture layout.- 2.4.3 Fixture element design.- 2.4.4 Fixture body design.- 2.5 Design criteria.- 2.5.1 Design specification.- 2.5.2 Factory standards.- 2.5.3 Ease of use.- 2.5.4 Cost.- 2.6 Design techniques.- 2.6.1 Axiomatic design.- 2.6.2 Rule-based design.- 2.6.3 Group technology.- 2.6.4 Parametric retrieval.- 2.6.5 Algorithms and analysis tools.- 2.6.6 Design procedure.- 2.7 Conclusions.- 2.8 References.- 3 Tolerance control and location surfaces.- 3.1 Manufacturing tolerance stacks.- 3.2 Tolerance charts.- 3.3 A new tolerance charting algorithm.- 3.4 CAPPFD.- 3.5 Conclusions.- 3.6 References.- 4 Flexible fixture systems.- 4.1 Introduction.- 4.2 Evaluation of fixture systems.- 4.2.1 Capital cost.- 4.2.2 Recurring cost.- 4.2.3 Fitness for purpose.- 4.2.4 Short-term flexibility.- 4.2.5 Long-term flexibility.- 4.3 Flexible fixturing.- 4.3.1 Modular fixtures.- 4.3.1.1 Baseplate, riser blocks and tooling blocks.- 4.3.1.2 Locators, supports and clamps.- 4.3.1.3 Tooling cubes, modular blocks and shims.- 4.3.1.4 Evaluation of modular fixture systems.- 4.3.2 Flexible pallet systems.- 4.3.3 Phase-change fixtures.- 4.3.3.1 Authentic phase-change fixtures.- 4.3.3.2 Pseudo phase-change fixtures.- 4.3.4 Conformable fixtures.- 4.3.5 Programmable fixtures.- 4.4 Conclusions.- 4.5 References.- 5 Computer-aided fixture design.- 5.1 Computer-aided design of fixtures.- 5.2 Approaches in fixture design.- 5.2.1 Variant fixture design.- 5.2.2 Generative fixture design.- 5.3 Fixture design techniques.- 5.3.1 CAD tools for fixture design.- 5.3.2 Group technology concept for fixture design.- 5.3.3 AI and expert systems in fixture design.- 5.3.4 Optimization of fixture configurations.- 5.4 Fixture design systems.- 5.4.1 Interactive fixture design systems.- 5.4.2 Semi-automated fixture design systems.- 5.4.3 Automated fixture design systems.- 5.5 A variant fixture design system using GT.- 5.5.1 A feature-based classification and coding scheme.- 5.5.2 Case indexing.- 5.5.3 Case retrieval.- 5.5.4 Case modification.- 5.6 A generative fixture design system using an expert system.- 5.6.1 Workpiece design module.- 5.6.2 Fixture design module.- 5.6.3 Case studies.- 5.6.4 System implementation.- 5.7 References.- 6 Analysis methods for workpiece distortion and deflection.- 6.1 Introduction.- 6.2 Clamping devices.- 6.2.1 Basic requirements.- 6.2.2 The magnitude and distribution of clamping forces.- 6.2.3 Types of clamping devices, clamping action and theoretical estimation of clamping forces.- 6.2.3.1 Screw clamps.- 6.2.3.2 Strap clamps.- 6.2.3.3 Toggle clamps.- 6.2.3.4 Power clamps.- 6.3 Machining forces, force models for milling and drilling.- 6.3.1 Milling force models.- 6.3.2 Drilling force models.- 6.4 Theoretical formulation of workpiece deformation using analytical methods.- 6.4.1 Modelling of workpiece deformation.- 6.4.2 Parameters considered in simulating workpiece deformation.- 6.4.3 Simulation results.- 6.4.3.1 Using parameters as shown in Table 1.- 6.4.3.2 Using parameters as shown in Table 2.- 6.5 Conclusions.- 6.6 References.- 7 Future trends and developments in fixturing methodologies.- 7.1 Introduction.- 7.2 An industrial perspective on fixture design.- 7.3 Future design methodologies.- 7.3.1 Concurrent engineering and fixture design.- 7.3.2 Generic fixture design.- 7.3.3 Case-based learning.- 7.4 Fixturing techniques.- 7.4.1 Modular fixtures.- 7.4.2 Phase-change fixtures.- 7.4.3 Vision systems.- 7.4.4 Dynamic fixtures to meet uncertainties and changes in scheduling.- 7.5 References.