Parametric Study of a Magnetorheological Fluid in a Finishing Process for Hard Materials

A magnetorheological (MR) fluid is useful in surface finishing process to finish complex-shaped workpieces selectively, and it has an advantage of causing little damage thereto. However, this finishing process in conventional way may be inappropriate for finishing hard materials such as hard disk sliders due to the potential lack of sufficient amount of material removal capability. Furthermore, it is found that wheel-type MR finishing tool has a severe limit to be applied for obtaining high polishing efficiency due to the centrifugal force inherent in the rotational motion of the tool. To resolve the problem of conventional rotational tool, we try to rectilinearly alternate the workpiece in addition to the existing rotational motion of the MR finishing tool. By superposing the two motions, relatively high velocity can be obtained, and it is found that it plays a great role in increasing material removal rate and decreasing surface roughness. In addition, parameters are studied that are also important in finishing hard materials. A theoretical model that can explain the wear mechanism of the finishing process at hand is proposed, and the results are compared with the experimental ones to support the validity of the proposed model.