Suppression of Repetitive Patterns in CNC Polishing by Random Circular Tool Paths

Abstract

In optics field, removing repetitive patterns on polished surface is important for refraining light interference. An algorithm for generating random circular paths was implemented. Polishing simulations and polishing runs with a raster path and a random circular path were performed on photomask, and waviness of polished surfaces was analyzed by Fourier transform. In polishing runs, amplitude of peaks in the wavelength region was suppressed with a random circular path, 0.5 nm, compared with a raster path, 0.9 nm. At this time, positioning and velocity errors of polishing machine were compensated by changing command value of NC code.