Renewable magnetorheological finishing tool combined self-rotation and co-rotation movement

The removal stability has an important effect on the surface accuracy during fine polishing of free-form optical surfaces and the polishing fluids must be renewed to safeguard the stability. This paper presents a polishing tool that combines self-rotation movement with co-rotation while renewing the polishing fluids. This tool maintains removal stability by renewing and combining the magnetic chains in the polishing fluids. The theoretical removal profile predicted using the lubrication theory of rigid bodies agrees well with that by experiment. The variation of the peak removal rate over time shows that the polishing continues to be stable over time. A stable removal rate is the precondition for highly accurate magnetorheological finishing.