Optimization Of Polishing Path And Material Removal Based On CCOS

Optical components are important components of the optical system and play an important role in the optical performance of the optical system.In recent years,with the improvement of optical performance requirements for optical systems,the requirements for processing accuracy and surface quality of optical components become more and more stringent.Polishing,as the last step in manufacturing optical components,directly determines the final surface accuracy and quality of optical components.Computer Controlled Optical Surface Forming（CCOS）technology can greatly improve the polishing accuracy and efficiency of optical components because its tool head can well adapt to the surface characteristics of the workpiece and make full use of the advantages of fast computer response and high repetitive execution accuracy.Polishing path planning is one of the key technologies in CCOS polishing,which directly affects the polishing accuracy,surface quality and polishing efficiency of the polished workpiece.The uniformity of material removal is of great importance to the surface accuracy and quality of the polished workpiece and is one of the important purposes of polishing path planning.In recent years,much research on path planning has mainly improved the uniformity of material removal by uniformly covering the path on the surface,uniformly covering the contact area or uniformly overlapping the contact area.However,these studies do not consider specific material removal and its changes and do not directly guarantee the uniformity of material removal.In this paper,the direct relationship between polishing path and material removal is established by applying the material removal profile,and the optimum research on planar scanning path,concentric circle path and the aspheric spiral path is carried out respectively around the uniformity of material removal during polishing.This paper mainly includes the following parts:1.Based on the Preston equation and Hertz contact theory,a material removal profile model considering polishing posture was established for continuous moving polishing of the spherical tool head along straight and curved paths.Subsequently,the Preston coefficients of polishing K9 glass and aluminium alloy with polyurethane tool head were determined by the fixed-point polishing experiment.Finally,through a series of simulation and polishing experiments,the influence laws of path curvature,surface curvature,polishing posture and other process parameters on material removal profile are analyzed,which lays a key theoretical foundation for the next path planning in this paper.2.To solve the problem of uniformity of material removal for the scanning path and concentric circle path of the flat surface,the two paths are respectively studied by combining path planning and material removal optimization.First,the overall material removal is predicted and analyzed by establishing a 3D material removal map for both polishing paths.Secondly,the theoretical expression of the 2D material removal profile is derived,and the relationship between path interval and process parameters and material removal uniformity and removal depth is revealed by calculating the 2D material removal profile.Then,the uniformity of material removal can be improved by optimizing the path interval,polishing posture angle and feed speed.In addition,the problem of overpolishing the edge area of the scanning path is improved by optimizing the feed speed of the edge path.Over-polishing of the centre area of the concentric circle path is improved by optimizing the radius,polishing inclination and feed speed of the centre circle path.The feasibility of the above method is preliminarily verified by simulation of the material removal map.3.In aspheric polishing,the Archimedes spiral paths result in poor uniformity of material removal due to variations in surface curvature and projection interval of the workpiece.A new path called Archimedes spiral path optimization is proposed to ensure uniformity of material removal depth in aspheric polishing.The method takes into account the influence of curvature of the aspheric surface on material removal and the influence of path interval on the superposition of adjacent paths.Firstly,2D material for calculating the aspheric meridian section is used to remove contour by material removal profile,and the traditional path is simulated and analyzed.Subsequently,a path interval search algorithm based on material removal profiles is proposed to generate an optimized Archimedes spiral path.Finally,the optimized path is simulated and the effectiveness of the proposed path generation method is preliminarily verified by comparing it with the traditional path.4.The feasibility of the optimization methods for the scanning path and concentric circle path of the flat surface and spiral path of the aspheric surface proposed in this paper is verified by experiments.The experimental results show that the proposed path planning method can improve the uniformity of material removal and the surface quality of the polished workpiece.