Experimental Investigation of Electro-Discharge Machining on NIMONIC 80A Through Response Surface Methodology

Electro-discharge machining (EDM) is one of the most popular advanced machining processes for machining conductive material irrespective of material physical properties. In the present study, effect of electro-discharge machining parameters such as current (A), pulse on time (T_on) and pulse off time (T_off) on machining characteristics such as material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR) of NIMONIC 80A is focused. The Box–Behnken design (BBD) of response surface methodology (RSM) was used to design the experiments, and also, analysis of variance (ANOVA) was conducted in order to know the most significant parameters. ANOVA results show that current and pulse on time were the most significant factors for material removal rate, and only current was significant parameter for tool wear rate and surface roughness. Multi-objective optimization process was conducted to maximize the MRR and to minimize the TWR and SR, and optimized parameters are “3 A” current, “900 µs” pulse on time and “30 µs” pulse off time with the desirability value of 0.988.