Title: Optimisation and influence of process parameters for machining oil hardened non-shrinking steel (OHNS) in wire-EDM

Authors: Nixon Kuruvila; H.V. Ravindra

Addresses: Dept. of Mechanical Engineering, Sahrdaya College of Engg. & Tech, Thrissur – 680684, India. ' Dept.of Mechanical Engineering, PES College of Engineering, Mandya – 571401, India

Abstract: The present study aims at determining parametric influence and optimum process parameters of wire electro discharge machining (WEDM) using Taguchi's technique and genetic algorithm. The variation of the performance parameters with machining parameters was mathematically modelled by regression analysis method. The objective functions are dimensional error (DE), surface roughness (SR) and volumetric material removal rate (VMRR). Pulse-on duration, current, pulse-off duration, bed-speed and flushing rate have been considered as the important input parameters. The matrix experiments were conducted for the material oil hardened non-shrinking steel (OHNS) having the thickness of 40 mm. The heat affected zone (HAZ) characteristics of the eroded material was assessed by scanning electron microscope (SEM) and the microhardness of the material was tested using Vickers microhardness tester. The results of the study reveal that among the machining parameters it is preferable to go in for smaller pulse-off duration for achieving over all good performance. Finally, the validation exercise performed with the optimum levels of the process parameters. The results confirm the efficiency of the approach employed for optimisation of process parameters in this study.

Keywords: wire EDM; electro-discharge machining; WEDM; electrical discharge machining; dimensional errors; surface roughness; surface quality; volumetric MRR; material removal rate; VMRR; Taguchi methods; regression analysis; genetic algorithms; GAs; optimisation; process parameters; oil hardened steel; non-shrinking steel; microhardness.

DOI: 10.1504/IJMMM.2012.050435

International Journal of Machining and Machinability of Materials, 2012 Vol.12 No.4, pp.372 - 397

Received: 08 Nov 2010
Accepted: 22 Jul 2011
Published online: 23 Aug 2014 *

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