Optimizing of Novel Magnetic Field-Assisted Electrical Discharge Turning Parameters for Machining EN24 Steel Alloy Using Response Surface Methodology and MCDM-Based CRITIC–TOPSIS Method

Abstract

This study employs a multi-criteria decision-making (MCDM) technique to identify the optimal parameters for the electrical discharge turning (EDT) process used to machine cylindrical EN24 steel alloy. EDT, a significant configuration of EDM, offers a valuable approach for machining cylindrical workpieces. A face-centred central composite design (FCCCD) is employed to establish the experimental design. The CRITIC–TOPSIS method is subsequently implemented to optimize the input parameters: gap current (Ig), pulse on time (Ton), rotational speed (N), and magnetic field assistance (B). Each parameter is investigated at three distinct levels. The study focuses on four response variables: material removal rate (MRR), tool wear rate (TWR), overcut (OC), and surface roughness (R_a). Analysis of variance (ANOVA) is conducted to assess the influence of each input parameter on the observed responses. Criteria importance through inter-criteria correlation (CRITIC) is employed to assign weights to each response, followed by applying the technique for order of preference by similarity to ideal solution (TOPSIS) to identify the ideal machining parameters. The results indicate that run number 16 (Ig: 16A, Ton: 60 µs, N: 1400 RPM, and B: 0.30 T) represents the optimal configuration. Scanning electron microscopy (SEM) analysis further corroborates this finding, confirming superior surface quality compared to other experimental runs.