Research On Off-axis Hyperboloid Machining Technology Based On Ion Beam

In modern science,the design and manufacture of optical systems has always been the focus of research in the field of optical science,and aspheric surfaces are more and more widely used in optical systems.Among them,off-axis hyperboloids play an important role in many optical systems.The effect of off-axis and asphericity affects its processing quality,thereby affecting the imaging quality of the optical system.As a non-contact deterministic polishing method,ion beam processing has been paid more and more attention in the manufacture of high-precision optical components.In this paper,the processing technology of off-axis hyperboloids is studied by means of ion beam processing.For the optimized off-axis hyperboloid,the closest spherical solution is carried out.Accordi-ng to the design requirements of the off-axis Cassegrain system,the system is designed and optimized.According to the design results of the off-axis hyperboloid as the secondary mirror,the diameter is ?40mm.The off-axis hyperboloid with the axis amount of 40 mm,the conic coefficient of-9.584,and the vertex curvature radius of-920 mm is the closest to the spherical surface,and the minimum material removal amount is obtained;based on the one-dimensional search method,the closest spherical surface is obtained,and the closest spherical surface of the off-axis hyperboloid is calculated and solved.The radius of curvature of the closest spherical surface is 938.7061 mm,and the maximum asphericity is 3.815 μm.Based on the characteristics of the radio frequency ion source,the ion beam removal function of K9 material was determined by Faraday cup and single-point etching methods,and the processing parameters of K9 material were obtained through dwell time simulation and process experiment.Finally,the experiment and testing of off-axis hyperboloid machining process are carried out.It is determined that the large beam diameter and the small beam diameter are connected in series to carry out the processing technology experiment;the off-axis Hindle sphere method is used to detect the off-axis hyperboloid,and the RMS value of the off-axis hyperboloid is finally0.026λ,and the PV value is 0.401λ,to meet the requirements of the processing index,through the exploration of the processing technology of the off-axis hyperboloid,a relatively mature and stable off-axis hyperboloid ion beam processing technology is obtained,which provides technical support for the high-precision processing of the off-axis hyperboloid.