Improved magnetorheological finishing process with arc magnet for borosilicate glass

Abstract

ABSTRACT In the process of magnetorheological polishing of planar optical elements, in order to solve the problem of uneven material removal rate and improve the polishing efficiency of planar optical elements. The finite element simulation was used to optimize the shape of the permanent magnet, and an arc permanent magnet was designed with a radius of curvature of 55 mm. The magnetic flux density of the arc permanent magnet has a Gaussian distribution, which effectively attenuates the effect of linear velocity on polishing. The arc permanent magnet is beneficial to achieve a more uniform material removal and better processing quality. The experiments are conducted on the borosilicate glass using the recent arc permanent magnet and existing planar permanent magnet. The experimental results show that the arc permanent magnets can reduce the average surface roughness value from 286 nm to 16 nm and the standard deviation of surface roughness to 0.92 under the same processing parameters. Therefore, the analysis of the borosilicate glass surface verifies that the designed arc permanent magnets can effectively improve surface accuracy and surface topography .