Development of Magnetorheological Finishing (MRF) Process for Freeform Surfaces

One of the newly developed methods for obtaining super finished surfaces for freeform is Magnetorheological finishing (MRF). MRF is an advanced finishing process in which the grinding force is controlled by magnetic field. The material removal in MRF is governed by the magnetorheological fluid which mainly consists of carbonyl iron (CI), abrasives particles, carrier fluids and additives. MRF process is capable of giving nanometer-scale surface finish. The process makes use of a magnetorheological fluid as a tool that acts as a flexible magnetic abrasive brush (FMAB) that provides finishing action. The relative motion between the finishing medium and the workpiece can be obtained either by rotating the workpiece, rotating the finishing medium, or both. In the present work, a setup has been developed for MRF application using a pillar drilling machine. Experiments were conducted to finish free form jobs of copper material using the developed setup. The effects of various process parameters viz. composition of the MR fluid, rotational speed of work and vessel containing MR fluid, mesh size of abrasives on surface finish were explored.