Aspheric machining technology based on vibration polishing of loose abrasive grains

With widely uses of aspherical optical elements, aspherical machining technology has become hot study topic. This paper presents aspheric processing method based on vibrating polishing of loose abrasive grains. Surface of aspherical optical element fully contacts with loose abrasive grains, and acting force of polishing for loose abrasive grains is provided by vibrating device. In this way, free materials is remove evenly and surface roughness is reduced Taking optical parts with size for Φ55 mm and material for ZK-10L as experiment specimen, influence on polishing effects are analyzed by vibration amplitude, the concentration of polishing liquid, and the impact of particle size and polishing time. When vibration amplitude, concentration of polishing liquid and particle size are 5 mm, 80 g/L and 1mm respectively, surface roughness of the specimen is reduced to 9.4 nm from 84.4 nm after 8h polishing, while specimen surface shape accuracy stays unchanged. In this way purpose of polishing specimen with high-accuracy surface shape is reached.