Experimental investigation of a novel magnetorheological process based on three revolving curved tip tools for finishing of mild steel

Abstract

High-quality surface of the cylindrical workpieces would have to be very precise when used in automobile industries, vane pumps, turbines, gears, mild steel dies and punches for plastic industries. The magnetorheological finishing process based on three revolving curved tip tools has been developed for external cylindrical components to address the above issues. Three electromagnetics tools have been used in this magnetorheological method that can move radially inwards or outwards according to the external diameter of the workpiece. During finishing, the workpiece rotates in the anti-clockwise direction, and three curved tip tools revolve around the workpiece in a clockwise direction resulting in more interaction between the workpiece and active abrasive particles. Reciprocating movement is also provided to the workpiece that helps to produce the axial force on the active abrasive particles. The proposed method has been applied to a mild steel shaft to investigate the surface finish of its external surface. Response surface methodology (RSM) has been used to plan and analyse the impacts of different process factors on the percentage change in surface roughness value of the finished surface of the mild steel stepped cylindrical shaft. The optimal combination of process parameters is magnetising current 3.4A, revolving speed of tools 26 rpm, the rotational speed of workpiece 440 rpm, and transverse speed of workpiece 20 cm/min, which shows the maximum percentage change in the surface roughness value. Confirmation experiments have been performed at optimal combination. The lowest Ra value of 85 nm (nanometre) has been achieved from the initial value of 410 nm (nanometre) in the finishing duration of 90 min. The roughness profiles, scanning electron microscopy (SEM) test and reflection test show that the current finishing process can meet high standards for surface quality that aren't possible with conventional methods.