Ultra-precision finishing of micro-aspheric mold using a magnetostrictive vibrating polisher

Demands of micro-aspheric glass lenses are increasing in optical devices such as digital cameras and blu-ray players. In this paper, a novel vibration-assisted polishing machine using a magnetostrictive vibrating polisher is proposed and developed to improve the efficiency, surface roughness and stability of finishing. The magnetostrictive vibrating polisher can generate a radius of 30 μm circular vibrating motion at frequency 9.2 kHz. From the polishing experiments, a smooth removal function was obtained. The form accuracy was improved to less than 100 nm P–V and the surface roughness was reduced to 3.3 nm Rz (0.4 nm Ra).