Parametric Optimization for Surface Roughness in Wire Electrical Discharge Machining— A Taguchi Approach

High carbon high chromium alloy tool steels (D-3) with excellent abrasion resistance (HRC: 58-65) are increasingly used in manufacturing high performance cutting tools (dies and punches), blanking and punching tools, extrusion tools, etc. Being a hard material, it is difficult to machine using conventional machining methods. Wire Electric Discharge Machine(WEDM) seems to be a viable option to machine such difficult to machine materials. In this paper, the effects of various process parameters of WEDM like pulse width, time between two pulses, maximum feed rate, servo reference mean voltage, short pulse time and wire mechanical tension, have been analysed for optimizing surface roughness(sr) while machining D-3 material. Experimental investigation based on Taguchi’s L-27 orthogonal array has been done. Signal-to-Noise (S/N) ratio, Analysis of Variance (ANOVA) and various plots are utilized to predict the optimal set of process parameters to minimize the surface roughness. The confirmation experiments have also been conducted to validate the results predicted by Taguchi technique.