Multi-Response optimization of AISI M42 HSS Material in Wire-Cut EDM using grey relational analysis

Wire Electro-discharge machining (WEDM) process consists of large number of variables. The selection of optimal combination of process parameters helps to achieve the optimal performance but, large number of variables makes it difficult. WEDM needs the multi-response optimization technique to achieve this. The goal of current research work is multi-response optimization of AISI M42 HSS material using Grey relational analysis (GRA) in WEDM. The pulse on time (Ton), pulse off time (Toff) and wire feed rate (Wf) are selected as process parameters. The Grey relational grade was calculated by adopting four different weight systems. The study reveals that, the most significant factors for MRR, SR and kerf width are Ton followed by Toff. The obtained optimal combination for three weighted GRG is A2-B3-C1 i.e., wire feed rate 6m/min, pulse on time 114μs and pulse off time 50μs. At this level the MRR of 7.2020mm3/min, SR of 3.29μm and KW of 0.317mm could be achieved. For average GRG, the optimum combination is A2-B3-C3. i.e., (wire feed rate-6m/min, pulse on time-114μs and pulse off time-56μs). At this level the MRR of 5.2894mm3/min, SR of 3.07μm and KW of 0.3028mm have been achieved.