Multi-performance optimisation in WEDM using Taguchi method embedded with utility concept

Traditional design of experiment approaches is suitable for single response problems. However, manufacturing industries need that products/processes must be evaluated based on the performance of several quality characteristics. In the present study, an investigation is made to simultaneously optimise two responses such as surface roughness and dimensional deviation in wire electrical discharge machining (WEDM) using utility concept coupled with Taguchi method. Experiments were conducted varying the process parameters namely pulse-on-time, pulse-off-time, wire feed, wire tension, spark gap, set voltage and servo feed. The machining parameter settings were determined using Taguchi's L27 orthogonal array. The individual surface roughness and dimensional deviation values are transformed into corresponding utility values. Individual utility values have been finally aggregated to compute overall utility degree which serves as representative objective function for optimisation using Taguchi method. The significance of the machining parameters is identified by analysis of variance (ANOVA) and the confirmation test has been conducted to validate the results. Experimental results reveal that the proposed method effectively improves the machining performance of WEDM process.