Application of TGRA-Based Optimisation for Machinability of High-Chromium Tool Steel in the EDM Process

It is essential to establish multi-criteria decision-making for computing the optimal process factors required to enhance the performance of the electrical discharge machining (EDM) process. For this purpose, criteria decision-making based on the Taguchi–grey analysis was employed in this study. Several responses such as material removal rates, average surface roughness, microhardness, and average white layer thickness were chosen to evaluate machinability. From the existing factor combinations, the optimum electrical factors that resulted in improved surface performance measures were identified as a peak current of 5 A, gap voltage of 50 V, pulse on time of 18 µs, and pulse off time of 37 µs, with a standard deviation within 4.1%. The maximum high- and low-grade value shows that the peak current affects performance measures, as it is essential in determining the spark energy in the EDM process. Moreover, significantly improved surface performance measures were achieved using the optimal process parameter combinations for the EDM process.