Abstract: Base on magnetorheological effect and cluster principle, the cluster magnetorheological effect plane polishing technology is proposed. The magnetic field characteristics of pole arrangement, the pole tip shape and different magnetic pole size are analysed by static magnetic field finite element software. It is found that soft polishing pad is more easily composed of multiple independent micro grinding head by select cylindrical flat bottom magnetic pole and arrange in the same direction, then the contact area of workpiece and micro grinding head maximization can be realized. By setting the contact state between the workpiece and the micro grinding head size and number, arc polish belt of K9 glass, single crysta silicon wafers and single crystal 6H-SiC wafers are polished for testing and verifying the cluster characteristics of micro grinding head. Optimization experiments are conducted to optimize the machining gap between the workpiece and the polishing disc surface, polishing time, the magnetic field strength of disk end and speed. By polishing K9 glass, single crysta silicon wafers and single crystal 6H-SiC wafers with the optimized parameters, nanoscale roughness surface are obtained in 30 min. The surface roughness of K9 glass, single crysta silicon wafers and single crystal SiC can be reduced from Ra 0.34 μm to Ra 1.4 nm, Ra 57.2 nm to Ra 4 nm and Ra 72.89 nm to Ra 1.92 nm, respectively.

Key words: cluster magnetorheological effect;plane polishing;semi-fixed abrasive;surface roughness;hard and fragile materials