Multi-objective optimization of process parameters in electro discharge machining of Inconel 625 superalloy with different electrode materials

Abstract This study focuses on the electrical discharge machining (EDM) of Inconel 625 superalloy using different electrode materials. The primary objective is to evaluate the influences of key EDM factors and electrode types (copper, tungsten-copper alloy, and graphite) on surface quality, material removal rate (MRR), and electrode wear. To this end, EDM experiments were systematically designed and conducted using the Taguchi-based grey relational analysis method. The results indicate that discharge current plays a critical role in improving machining performance. When machining Inconel 625 with copper electrodes, the surface quality improves by approximately 90.57 % and 63.92 % according to W–Cu and graphite electrodes, respectively. Additionally, under optimal processing conditions, W–Cu electrodes exhibit wear rates that are approximately 7.59 % and 20.25 % lower than those of graphite and copper electrodes, respectively. In terms of material removal rate, graphite electrodes outperform copper and W–Cu electrodes by 206.28 % and 123.33 %, respectively. Statistical analyses further confirm that the predictive models developed for optimizing process conditions provide highly accurate and reliable results.