Machining performance of high energy die-sinking electrical discharge machining on GH2132

Superalloys are typical "difficult to machine" materials, which could be processed by electrical discharge machining (EDM). The studies about the machining performance of superalloys mainly concentrate on nickel-based superalloys and titanium superalloys. But for iron-based superalloys, such as GH2132, which has an extensive application in numerous fields, the investigations are seldom conducted. A high energy die-sinking EDM is proposed in this paper, and the deionized water is used as the dielectric. The machining performance of GH2132 through the proposed machining method is systemically investigated. Taguchi L25 orthogonal array (L25) is utilized to investigate the influences of machining parameters (peak current (I), pulse on time (Ton), and pulse off time (Toff)) on output indexes (material removal rate (MRR), relative electrode wear rate (REWR), and diameter overcut (DOC)). Single-objective optimization is performed to acquire maximum MRR, minimum REWR, and DOC by analysis of variance (ANOVA). The optimal machining performance, which is better than the results from L25, is also obtained by gray relation analysis (GRA) and multi-objective optimization.