Genetic algorithm based deformation control and clamping force optimisation of workpiece fixture system

Abstract

In re-engineering mass production industry, design and production of components are frequently changed according to the customer needs within a very short span of time. This leads to rising difficulty in maintaining the accuracy of every finished component. It also induces the long setup time of the cutting tools and machine tools affecting the production rate of the components. To reduce the production time and to improve the accuracy of the finished product, proper fixture element is essential. The accuracy of the finished work-piece strongly depends on the position of the locators and clamps in the work-piece fixture system. The finite element analysis tool is well suited to predict the active and passive forces on the work piece-fixture system. The accuracy of the workpiece not only depends on the clamping force but also depends upon the locator force (reaction force). This paper presents the optimisation of the locations of active (clamp) and passive (locator/support) elements in the workpiece-fixture system using genetic algorithm (GA) with ANSYS parametric design language (APDL) of finite element analysis. Three case studies are given to illustrate the application of the proposed approach. Finally the case study results have been compared with the Li and Melkote (1999a) [Li, B. and Melkote, S.N., 1999a. An elastic contact model for the prediction of workpiece-fixture contact forces in clamping. ASME Journal of Manufacturing Science and Engineering, 121(3), 485–493] study. This presented prediction method is conceptually simple and computationally efficient.

Keywords:

• active element
• passive element
• genetic algorithm
• finite element analysis

Acknowledgements

The authors would like to thank Dr Kalyanmoy Deb, KanGal, IIT, Kanpur, for the GA code used in this study.