Trajectory optimization of the center-inlet elastic polishing tool for uniform material removal and mid-spatial frequency error suppression on optical elements

Abstract

To acquire uniform material removal and suppress mid-spatial frequency error of optical elements applied to laser devices, this paper proposed a combined processing scheme based on the center-inlet elastic polishing tool, which is an important component in the computer controlled optical surfacing process. Considering the special structure of the polishing tool, a material removal model under a continuous feed state was established. Trajectory optimization strategy integrating path distance analysis with a novel layered reshaping method was proposed. The optimized path distance significantly enhances material removal uniformity, while the proposed depth-controlled layered reshaping effectively suppresses mid-spatial frequency error caused by excessive path repetition. In addition, a high-precision offline simulation platform demonstrating exceptional predictive capability was established, which achieved less than 10 % deviation between simulated and experimental removal profiles. The experimental results show that the surface roughness Sa and Ra of the samples were improved by 89.4 % and 94.9 % through the combined processing scheme, respectively, while the curve of PSD decreased obviously, which indicates that the mid-spatial frequency error was effectively suppressed. The demonstrated consistency between simulation predictions and physical processing outcomes establishes a valuable reference for precision optical elements’ process optimization.