Basic study on ultra-precision grinding of optical glass lens by CeO₂chemical reaction assistance

Large aperture lenses which are used for single-lens reflex cameras and astronomical telescopes are manufactured by both ultra-precision grinding to make precise shape and polishing to improve surface quality. However, prolonged polishing deteriorates lens shape accuracy and decreases productivity. In order to reduce polishing amount and obtain finer surface without cracks before polishing, it is required to develop a highly-efficient ductilemode grinding technology. In this study, a novel ultra-precision grinding method assisted by CeO₂chemical reaction is proposed and its performance is experimentally evaluated. The results show that crackless surface can be successfully obtained over the entire surface at three times higher tool feed rate, compared with conventional grinding without CeO₂assistance.