Development of quality microholes by electrical discharge drilling on Al/SiC composite using of Grey-desirability approach

Abstract

Electric discharge drilling (EDD) is a variant of spark erosion machining and is successfully used for the drilling of quality microholes. In present research, an attempt was made to drill microholes on Al/SiC composite. The drilling on aluminum composite was made at different machining indicators to analyze its effect on drilling rate (DR), electrode wear ratio (EWR), hole overcut (HO) and circularity (C). The input parameters selected in this work are pulse on-time (Ton), peak current (Ip) and pulse off-time (Toff). The experiments were planned as per Taguchi's L9 orthogonal array (OA). It was found that with the increase in Ton value, HO and EWR increases. However, larger values of Ip and Toff decreases the HO and EWR. Due to the combination of different quality characteristics Grey theory along with desirability has been implemented for collective response of output parameters. The optimized setting for multiple performance characteristics is Ton: 40; Ip: 3; Toff: 50. An improvement of 0.0199 is observed in grade value during optimization as compared to the maximum calculated grade value. After the implementation of proposed optimization technique, an improvement of 42.88% in DR, a reduction of 33.59% in EWR, a reduction of 4.54% in HO and 0.68% in C is observed.