Comparative performance of magnetorheological external finishing tools using different magnetic structures

Abstract

The operative functionality of various mechanical parts depends on surface characteristics; therefore, surface roughness becomes vital for reducing the friction between the two mating surfaces. Currently, the grinding operation is used for finishing these mechanical parts. The grinding tool is generally made by the bonded abrasive particles that contact the part surface during the finishing operation. In grinding, the finishing forces induced by the grinding tool are uncontrollable, which makes the process less effective for nano-finishing applications. Magnetorheological (MR) finishing technique is considered as a better option for nano-finishing applications. In this work, MR finishing tools with flat and curved cylindrical magnets are developed, which has the advantage of being flexible according to the diameter of cylindrical parts. Magnetostatic simulations are carried out to visualize the distribution of magnetic flux density using the developed tools. The experimentation was performed using the developed tools with parameters: workpiece rotation of 440 rpm, linear tool feed of 10 cm/min and tool travel path along x-axis of 3 cm during finishing of the external cylindrical surface of a stainless-steel workpiece. Results showed that after 60 min of finishing, the surface roughness (Ra) was decreased by 62.74% for curved cylindrical magnets and 53.81% for flat cylindrical magnets