EVALUATION OF EFFECT OF ECDM PROCESS PARAMETERS ON INCONEL 625 PERFORMANCE CHARACTERISTICS USING ENTROPY-TOPSIS

The present research focuses on the multi-objective optimization of electrochemical drilling machining (ECDM) of Inconel 625 using a Taguchi-based Entropy-TOPSIS approach. Unlike conventional studies that primarily consider material removal rate (MRR) and surface roughness (Ra), this investigation uniquely incorporates additional geometric accuracy measures such as overcut, form, and orientation tolerance errors. The integrated optimization framework successfully yielded a single optimal parameter setting of feed rate of 0.20 mm/min, flow rate of 0.75 L/min, and electrolyte concentration of 10% to achieve improved multi performance machining characteristics. The Taguchi analysis revealed that feed rate (F) and flow rate (Q) exhibit non monotonic effects, whereas electrolyte concentration (C) shows a clear monotonic decreasing trend, suggesting that F and Q should be adjusted around moderate levels while maintaining a lower C to enhance closeness coefficient (Ci +) performance. ANOVA results validated the statistical model with a high level of significance (P = 0.000), identifying F and Q as the most influential parameters, along with their strong interaction effect (F×Q). Although factor C alone was statistically insignificant, its interaction with Q was found to be meaningful. The developed regression model was confirmed to be reliable with high coefficient of determination values (R² = 94.23% and R²(adj) = 91.18%). Overall, the findings establish that the Taguchi-based Entropy TOPSIS method is a robust and effective approach for achieving optimal electrochemical drilling performance in Inconel 625, making it a valuable tool for addressing complex multi-response optimization problems in advanced machining applications.