Single-point inclined-axis error compensation grinding for small aspheric optical molds

A single-point inclined-axis grinding technique and error compensation method of aspheric mold are studied. After analyzing and comparing the traditional perpendicular grinding method, a the single-point inclined-axis grinding mode is proposed for avoiding the interference between small grinding wheel and small aperture aspheric mold, and the stability and grinding accuracy can be improved. Small fine grinding wheel with high intension is chosen by analyzing the interference of grinding area and the grinding wheel. An error compensation strategy is proposed based on ultra-precision single-point inclined-axis grinding. The x-directional and y-directional de-centering errors are considered to correct the new centering position of grinding wheel. The random form error is compensated based on proposed normal residual error compensation. An experimental test is conducted to grind an aspherical tungsten carbide mold with aperture 2 mm on an ultra-precision grinder. The profile accuracy is gradually improved from PV 1 034 nm to 146 nm after two-time compensation cycle, and the surface roughness is Ra 2.19 nm. © 2013 Journal of Mechanical Engineering.