Electrical discharge machining of EN-40B high carbon alloy steel: Investigation of recast layer and multi-performance optimization

Abstract

This study has investigated the machinability of EN-40 high-carbon alloy steel in electrical discharge machining (EDM) by analysing the recast layer morphology. Taguchi’s L16 design and the desirability function approach (DFA) with a simple optimization algorithm (SOPTA) have been used to optimize pulse on time (Ton), pulse off time (Toff), low voltage current(LV), and high voltage current (HV). Performance metrics have included rate of material removal (RMR), tool wear rate (TWR), and surface roughness (Ra). The SOPTA algorithm using MATLAB 22a has determined the optimal settings (LV = 25A, HV = 2A, Ton = 40 μs, Toff = 25 μs) with a composite desirability of 0.5784. A confirmatory test has verified the optimal setting and compared it with the initial setting. The experimental results have shown that EDM performance has been significantly enhanced by the proposed method, with RMR, TWR, and Ra having improved by 66.32%, 70.36%, and 55.64%, respectively.