Development of magnetorheological fluid-based process for finishing of ferromagnetic cylindrical workpiece

A magnetorheological fluid-based process is developed for the internal surface finishing of ferromagnetic cylindrical workpiece. The existing finishing processes based on magnetorheological fluid are not equipped to finish the internal ferromagnetic cylindrical surface significantly as it obtained higher magnetic flux density than the MR polishing fluid. At present, magnetorheological fluid-based finishing tools are designed to ensure the maximum magnetic flux density always present on the outer finishing tool core surface as compared to internal surface of ferromagnetic cylindrical workpiece surface. To validate this present principal idea, the magnetostatic finite element analysis has been performed on the newly designed finishing tools. The preliminary experiments have also been conducted to evaluate the finishing performance with the two newly designed finishing tools. The percentage reduction in surface roughness (R-a) values with I-shaped tool core is found as 65-78% after 150min of finishing, whereas, with rectangular shaped tool core is found as 78-81% after 90min of finishing. The results clearly revealed that the present finishing tool with rectangular shaped core is more suitable for uniform significant finishing of ferromagnetic cylindrical internal workpiece than the I-shaped core. The developed process can be useful in finishing of cylindrical mold and dies, hydraulic cylinder, barrel for injection molding, etc.