Modeling of finishing force and torque in ultrasonic-assisted magnetic abrasive finishing process

A new finishing technique called ultrasonic-assisted magnetic abrasive finishing integrates ultrasonic vibration with magnetic abrasive finishing process for finishing of workpiece surface more efficiently as compared to magnetic abrasive finishing in the nanometer range. During finishing, two types of forces are generated in ultrasonic-assisted magnetic abrasive finishing, namely, a normal force (indentation force) and a tangential force (cutting force) that produces a torque. The finishing forces have direct control on the rate of change of surface roughness and material removal rate of the workpiece surface. This article deals with the theoretical modeling of the normal force and the finishing torque based on the process physics. In this work, finite element simulations of the electromagnet were performed to calculate a magnetic flux density in the working zone; they were also used to evaluate the normal force on the workpiece surface. The theory of friction for the abrasion of metals was applied together with the effect of ultrasonic vibration to calculate the finishing torque. The developed model predicts the normal force and finishing torque in ultrasonic-assisted magnetic abrasive finishing as functions of the supply voltage, working gap and concentration of abrasive particles in a flexible magnetic abrasive brush. A comparison of theoretical and experimental results is performed to validate the proposed model.