Title: On process analysis and optimisation of wire electric discharge machining of Ti 6-2-4-2 using regression modelling and genetic algorithms

Authors: Mohinder Pal Garg; Ajai Jain; Gian Bhushan

Addresses: Dept. of Mechanical Engg., M.M. Engg. College, M.M. University Mullana, Haryana, India ' Dept. of Mechanical Engg., National Institute of Technology, Kurukshetra, Haryana, India ' Dept. of Mechanical Engg., National Institute of Technology, Kurukshetra, Haryana, India

Abstract: Titanium alloys are considered as 'metals of future' because of their exceptional properties such as high strength to weight ratio, high specific strength, corrosion resistance etc and there is a crucial need to develop cost effective methods for their machining. The present paper highlights the analysis of variation of objective functions namely, metal removal rate, surface roughness and dimensional deviation depending upon the process parameters of wire electric discharge machining in machining of Ti 6-2-4-2 alloy. Box-Behnken designs are used to plan and analyse the experiments. Mathematical models are developed for metal removal rate, surface roughness and dimensional deviation using regression technique and consequently opted for optimisation of objective functions. As the parametric effect on metal removal rate, surface roughness and dimensional deviation is opposite, the problem is considered a multi objective optimisation problem. Pareto optimal solutions satisfying the conflicting objective functions are obtained using non-dominated sorting algorithm -II. The solutions obtained so can be utilised as machining recommendations to set levels of process parameters to satisfy the set of aforesaid process yield criteria.

Keywords: wire EDM; multicriteria optimisation; titanium alloys; analysis of variance; Box-Behnken designs; BBD; ANOVA; NSGA-II; process analysis; electrical discharge machining; electro-discharge machining; regression modelling; genetic algorithms; metal removal rate; MRR; surface roughness; dimensional deviation; surface quality; mathematical modelling.

DOI: 10.1504/IJMMM.2015.071992

International Journal of Machining and Machinability of Materials, 2015 Vol.17 No.3/4, pp.185 - 210

Received: 23 Aug 2014
Accepted: 23 Jan 2015
Published online: 27 Sep 2015 *

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