Surface roughness optimization of new-generation WP7V tool steel in WEDM: a Taguchi and RSM approach

Purpose This study aims to optimize the surface roughness (Ra) of new-generation WP7V tool steel processed using wire electrical discharge machining (WEDM). The investigation identifies the most significant machining parameters and their effects using Taguchi and response surface methodology (RSM). Design/methodology/approach WP7V tool steel, a cold work tool steel with low thermal conductivity and excellent toughness, was processed using the Taguchi L18 orthogonal array and optimized through RSM. The input parameters were voltage (4–8 machine units/70–150 V), servo feed (SF) (60–100 mm/min), pulse-on time (Ton) (10–14 µs) and pulse-off time (Toff) (13–18 µs). Ra of the machined surfaces was measured using a Mahr MarSurf PS10 profilometer, and analysis of variance (ANOVA) was performed to determine the contribution of each parameter to Ra. Findings Ton and Toff were identified as the most critical parameters affecting Ra, contributing approximately 34% each. The optimal combination for achieving minimum Ra was determined as 150 V voltage, 100 mm/min SF, 10 µs Ton and 13 µs Toff. Predicted Ra values from Taguchi and RSM methods were validated against experimental results, showing strong agreement and reliability. Practical implications The study demonstrates that optimizing WEDM parameters can significantly improve surface quality for new-generation WP7V tool steel. The results provide practical guidelines for engineers and manufacturers to achieve cost-effective, high-precision machining. Originality/value This work highlights the combined use of Taguchi and RSM methodologies for optimizing Ra in machining advanced WP7V tool steel. The findings enhance the performance and applicability of WEDM for processing new-generation tool steels. Studies on WEDM of WP7V steel are extremely limited in the literature, making this research a valuable contribution to the field.