Magnetic field assisted batch nano-polishing of optical glass

Optical glasses with different geometries have been widely used in imaging, illumination, and light control. Nanometric surface roughness is usually required for these kinds of components. Various kinds of polishing methods have been developed for the polishing of optical glass in recent decades, such as magnetorheological finishing, ion beam finishing, bonnet polishing, fluid jet polishing, etc. However, the optical glass components are usually polished one-by-one by these processes, leading to high polishing cost and low production efficiency. In this paper, a novel magnetic field assisted batch nano-polishing (MABNP) method is proposed for the polishing of optical glass, which can not only implement polishing of a batch of components simultaneously, but also can obtain nanometric surface roughness and micro-meter scale surface form accuracy. Shape adaptive algorithm we recently developed was used to determine the optimal impinging angle to implement the material removal as uniform as possible. Case studies were conducted on the optical glasses with different geometries to demonstrate the polishing performance of MABNP. The results indicate that MABNP can successfully polish six optical glasses simultaneously to obtain nanometric surface roughness and micro-meter scale surface form accuracy within 15 minutes. The number of the optical component polished for one time can be further increased through changing the design of the fixture. This method paves a new way for the high-efficiency and low-cost nano-polishing of optical glasses. Moreover, MABNP method is also suitable for the fast and cost-effective nano-polishing of other non-ferromagnetic materials.