Enhancing surface quality of cylindrical mold punch made of P20 steel using a newly developed magnetorheological finishing process

This study investigates the effectiveness of a newly developed magnetorheological fluid (MRF) finishing process in improving the surface quality of P20 steel mold punches, which are crucial for producing smooth plastic components in casting. Surface quality of molds and punches improves product quality, enhances precision, reduces wear, optimizes material flow, minimizes defects, and extends the lifespan of the die and punch. The MRF finishing process utilizes abrasive particles suspended in MR fluid to achieve a fine surface finish. The research aims to evaluate the feasibility of the new developed MRF process for finishing hard materials and examines the influence of a new finishing parameter percentage of abrasive particle concentration along with four other key finishing parameters using the Taguchi method. After 45 min of finishing, a significant reduction in surface roughness is observed, decreasing from 0.247 µm to 0.065 µm. Among the parameters studied, abrasive particle concentration is identified as the most influential factor in achieving this reduction. To assess the process's effectiveness, the initial surface and the MR-finished surface are compared using a Taylor Hobson Surftest-25 roughness tester, scanning electron microscopy, and mirror image tests. The results confirm that the newly developed MRF process significantly enhances surface quality, reducing roughness to the nano level and refining the microscopic surface of the mold punch.