Experimental investigation of the influence of electrical discharge machining process parameters using response surface methodology

Electrical discharge machining (EDM) is one of the earliest nontraditional machining, extensively used in industry for processing, with reasonable precision, parts having unusual profiles. The quality of an EDM surface is strongly influenced by its parameters and the material to be machined. The objective of this work is to investigate the influence of the EDM process parameters to improve productivity and surface quality of manufactured products of 90MnCrV8 cold work steel alloy material. Moreover, an L₁₈ orthogonal array based on Taguchi method is adopted to formulate and conduct a series of experiments. The ANOVA method is used to identify the most influential process factors and their inter-relation to output responses and find the optimal parameters of EDM. The considered input parameters: voltage, current, pulse-on time, and pulse-off time are experimentally investigated with regards to their effects on material removal rate (MRR), surface roughness (SR), and white layer thickness (WLTh). The obtained results reveal the optimal level of input factors in order to maximize MRR and minimize both SR and WLTh performances. Additionally, it is concluded that the current play the most considerable role in EDM machining process followed by the other factors. The optimum levels are determined through developed empirical models for the considered output responses. Finally, validation tests are carried out showing a relative error in terms of MRR, quality Ra, and WLTh of less than 10%.