Controlling mid-spatial frequency errors in magnetorheological jet polishing with a simple vertical model.

Abstract

Mid-spatial frequency (MSF) errors are always produced in magnetorheological jet polishing (MJP) with a simple vertical jetting model and require a control during the process. The relation between a surface with MSF errors and power spectral density is analyzed. Based on this, various concepts and methods are developed to restrain the MSF errors in MJP. With a cut-off frequency, the appropriate removal function is adopted. In addition, a dedicated path with uniform characteristics is designed for polishing. The weighted iterative algorithm is proposed to get a continuous and effective dwell time map. The duplication ratio is utilized to increase the nonuniformity of the surface. The experiments are deployed in a MJP run. The peak-to-valley and root mean square of the surface are reduced from 0.384λ and 0.077λ (λ=632.8 nm), respectively to 0.054λ and 0.007λ, respectively, and the smooth PSD curves are produced with low and smooth distribution.