The study aimed to investigate the electric discharge machining (EDM) of Ti-6Al-4V (titanium alloy) with rectangular graphite electrodes. The experiments were conducted using L18 orthogonal array (OA) by Taguchi method, with three critical input parameters including pulse current (A: 4, 8, 12 Amps), pulse on time (B: 200, 400, 600 µs) and pulse off time (C: 20, 30, 40 µs). The electrode wear rate (EWR), metal removal rate (MRR) and surface roughness (Ra) were the responses considered in this work. The measured responses were optimized and modelled using Taguchi based grey relational analysis (GRA) and response surface methodology, respectively. Analysis of variance (ANOVA) was used to identify the most influencing EDM parameter. Further, the mathematical prediction model obtained from response surface methodology (RSM) produced a result that agreed with that of the experiment. The topography of the machined surfaces was examined using white-light interferometer (WLI).The improvement of EDM performance was around 57.26% by this projected approach.
