Parametric investigation and optimization of revolving tools-based magnetorheological finishing process for external cylindrical surface of printing machine roller made of copper

The cylindrical copper rollers are an essential part of the printing process. The copper roller needs to be finely finished to ensure the even distribution of the colors. Fine and precise polishing of cylindrical copper rollers is challenging using conventional finishing procedures because of their ductility and low hardness. Therefore, the magnetorheological finishing process based on three revolving flat-tip tools has been used to meet this precise requirement. The optimized parameters were found as current 3.5A for the electromagnet, rotating speed of the workpiece 510 rpm, revolving speed of the tools 35 rpm, working gap 0.7 mm and feed rate 150 mm/min for maximum percentage reduction in the surface roughness of copper roller. After 4 h of finishing with the optimal parametric settings, the Ra, Rq, and Rz values were reduced to 0.08, 0.1, and 0.67 mu m from the initial values of 0.375, 0.527, and 1.96 mu m, respectively, across the copper roller surface. Surface roughness profiles, SEM, and mirror-image tests reveal the superiority of the magnetorheologically finished roller surface compared to the unfinished one.