Parametric Analysis and Optimization of Wire EDM for Improved Surface Roughness of D2 Tool Steel Using Response Surface Methodology

This study presents a systematic investigation into the optimization of Wire Electrical Discharge Machining (WEDM) parameters for improving the surface finish of D2 tool steel. Utilizing Response Surface Methodology (RSM) integrated with Central Composite Design (CCD), the research aims to minimize surface roughness (Ra) through the controlled variation of critical process parameters: wire feed rate, pulse-on time, pulse-off time, peak current, and sensitivity. The optimal parameter configuration comprising a wire feed rate of 60 mm/min, pulse-on time of 32 µs, pulse-off time of 7 µs, peak current of 4 A, and sensitivity level of 5 resulted in a minimum surface roughness of approximately 3.7309 µm. These conditions enhanced process stability, facilitated efficient material removal, and reduced thermal damage, thereby preserving surface integrity. The developed regression model demonstrated high predictive accuracy, supported by a composite desirability index of 0.582. Experimental validation confirmed the reliability and repeatability of the optimized parameter set. The findings underscore the significance of multi-parameter optimization in achieving high-precision surface characteristics, offering practical insights for advanced machining applications in tool and die manufacturing.