A genetic algorithm-based solution to optimal tolerance synthesis of mechanical assemblies with alternative manufacturing processes: focus on complex tolerancing problems

Abstract

The product development process involves tolerance specification on the individual component dimensions. The impact of tolerance specification on manufacturing cost has drawn the attention of product designers towards economic tolerance synthesis using various optimization techniques. Simultaneous selection of manufacturing processes or machines from amongst the alternatives for producing a toleranced feature have also been considered. The solution surface for such a problem becomes a combinatorial and multi-modal function involving several local minima. Application of a genetic algorithm to the solution of this advanced tolerancing problem, together with benchmarking with the exact global solution obtained using Lagrange's multiplier-based exhaustive search method, has been reported in an earlier paper by the authors. The proposed algorithm is quite simple and straightforward, and automatically takes care of the process selection constraints. Application of the genetic algorithm has been demonstrated on complex tolerancing problems such as those involving interrelated dimension chains, complex stack-up conditions and complex cost functions, etc., where the use of traditional optimization techniques is not recommended.

Acknowledgements

The authors are very grateful to Professor Kalyanmoy Deb (Department of Mechanical Engineering, Indian Institute of Technology, Kanpur) for explaining the scheme of the application of GAs applicable to the aforementioned advanced tolerance synthesis problem. Sincere gratitude is also due to Professors K. W. Chase, H. A. ElMaraghy and Z. Dong in the international research community for extending their cooperation by providing a useful literature.