Grey relational analysis for multi-response optimization of process parameters in green electrical discharge machining of Ti-6Al-4V alloy

Abstract This paper presents optimization of process parameters in electrical discharge machining (EDM) of Ti-6Al-4 V alloy with multiple responses using grey relational analysis. The responses considered in this study are metal removal rate (MRR), surface roughness (Ra) and recast layer thickness (RLT) whereas process parameters are discharge current, pulse on time and pulse off time and graphite powder concentration(g/l). The approach uses weighted grey relational grade as performance index to determine optimal levels of parameters. Based on weighted grey relational grade, optimal levels of parameters are identified and their percentage contributions are determined by analysis of variance. It is found that pulse on time is the significant parameter for multi-response optimization in this study. The results of confirmation test indicate percentage improvements in MRR, Ra and RLT as 5.60%, 2.33%and 5.97% respectively. Hence grey relational analysis can be effectively used for continuous improvement in EDM quality in modern manufacturing industries.