An Efficient Aspherical Polishing Method

Aspheric optics with advantages of superior imaging characteristic and compact configuration are more and more widely used in precise optical instruments, that requires the development of mass production of aspheric. Now aspheric can be fast and precision grinded and generated. However, polishing process may still most influence the efficiency and accuracy of aspheric manufacture.In this paper a two-step polishing process which combined with whole aperture pre-polishing with large flexible form tools and correction polishing with small-tools is proposed to polish aspheric surface with middle aperture and replace the reiteration polishing processes. Compensating different stock removal of the tool in different lens areas is used to control the accuracy in pre-polishing process. Then based on Preston theory, corrective polishing with small-tools is optimized and the better removal function is obtained. Also a parameter related the radius of curvature is introduced and determined to increase the polishing precision, which is improved by experiments. A software controlled the polishing is programmed, and integrating the CAD/CAM technology, a procedure joined the optical design software to optical manufacture machines is advanced. The data formats of optical design software (CODE V) and optical CNC machines are investigated. Based on the function of optical design software that can output documents with file type of txt, we developed the software in Visual C++ used to control optical manufacture process. The software can find parameters of curve surfaces from the documents, handle the data stream of optical design software, the technological parameters of optical manufacture machines and surface error data of Talysurf, and simulate the manufacture process.After online debugging and experimenting, the surface error of 0.35 m P-V is achieved in short polishing cycle time. This optical CAD/CAM integrating manufacture provides a practical approach to mass production and popularization of aspheric optics.