Free-form Optical Surface Processing In Slowing Tool Turning And Simulation

As the core part of photoelectric products,free-form surface can greatly improve the electro-optical system's performance and decreased its size.Slow Tool Servo(STS)has been one of the crucial mode of ultra-precision machining with the introduction of advanced technology like spindle servo.Based on technology of STS,STS turning principle,tool-track planning,tool-parameter selection,tool-radius compensation algorithm,and machining error analysis have been studied in the thesis.The main content of this thesis is summarized as follows:(1)The dynamic model of the workpiece and the tool processing system is respectively established based on the dynamics theory through depth analysis of typical STS machine layout and the motion relationship between the axes,then the main structure of the machine tool is simplified.The steady state damping ratio of system is generated by analyzing system's step and shock response assuming there is no coupling conditions in the system.(2)Based on the principle of STS turning,the interrelation between each coordinate system in the process is built through analyzing the kinematic characteristics of each machine tool unit.To acquire the optimum geometric parameters of the tool in machining scheme,the constraint relationship between the tool geometric parameters and the surface is researched via utilizing the method to different cross section and surface intersection under the tool coordinate system.(3)In order to ensure the machining accuracy,which is based on the theory of STS turning path planning to freeform surface,the correction method of tool position point is studied by considering the dynamic characteristics of machine tool servo axis.The deficiencies in traditional algorithms that are the basis of isometric point are improved through coming up a novel one,which is proved that it effectively improves the accuracy of the surface machining.(4)The macroscopic cutting force model based on material deformation theory is set up through calculating the irregular area of cutting district.The error algorithm model for final machining result is concluded by analyzing force on the cutting tool,when tool-nose tip deviating from Rotation Axis.The error distribution is acquired through validating validity of the error model in test and numerical simulation.