Material removal mechanism of cluster magnetorheological effect in plane polishing

Abstract

A cluster magnetorheological (MR) plane polishing based on a combination of magnetorheological finishing (MRF) and cluster mechanism (arrange in a regular array) has been developed for large planar optical workpiece. In this paper, the polishing pressure of an individual MR micro-grinding head on workpieces was investigated, and the mathematical model for cluster MR plane polishing was established based on the Preston equation and the properties of the workpiece material. An arc-shaped polishing belt was processed on monocrystalline 6H-SiC and Si wafer by the cluster MR polishing apparatus which polishing disk inlaid with cylindrical flat bottom magnetic pole arrange in the same direction regularly and monocyclically. The profile of arc polishing belt’s cross section and the surface morphology were observed and analysed to verify the obtained model. The abrasives with different size were found to have an equal effect on the processed surface because of the accommodated-sinking effect of the polishing pad constituted by the cluster MR micro-grinding head. It was found that the monocrystalline 6H-SiC and Si wafer were polished in a plastic mode with a smooth, damage-free surface.