Numerical and experimental study of influence function in magnetorheological finishing of oxygen-free high conductivity (OFHC) copper

Study of influence function of finishing process is very important for setting the process parameters. In this article, influence function of magnetorheological finishing (MRF) process is investigated numerically and experimentally by studying the flow behaviour of magnetorheological (MR) fluid. A 3D computational fluid dynamics simulation is performed considering MR fluid as a Herschel–Bulkley fluid. Dynamic pressure and wall shear stress on the workpiece surface are determined for different working gaps and rotational speeds. Variable depth of indentation by abrasive particle on oxygen-free high conductivity copper is calculated numerically and correlated with the experiments. Depth and area of influence function increase with spindle speed and reducing working gap. Dynamic pressure decides the indentation depth which is related to normal force, whereas wall shear stress removes the material up to the indentation depth which is related to the tangential force. Influence function shows two separate regions at the edge of magnet due to variable magnetic flux density. Contact length of MR fluid with workpiece and squeezing of MR fluid play significant role in material removal. Experiments are carried out to study forces acting on the workpiece, indentation depth and validation of simulation results. (paper)