Techniques For Aspherical Turning Based On Swing Feed And Piezoelectric Servo Tools

Compared with spherical elements,aspherical optical elements have many advantages such as high imaging quality,small size,light weight,etc.,and their applications are more and more extensive.The application of aspheric surfaces is mainly limited to its manufacture and testing.At the same time,developed countries in foreign countries have blocked the technology of ultra-precision machine tools in China.Therefore,it is extremely important to study aspheric surface processing technology.Aspherical machine tools based on swinging feed of piezoelectric servo tools Compared to traditional T type machine tools,only the rotation of the main shaft and the swing arm does not have the movement of the linear guide,which is advantageous for processing large-aperture aspheric optical elements.At the same time,based on the piezoelectric ceramic tool holder can achieve accurate micro-displacement movement,which is conducive to asphericity when the swing arm swings.Based on this,starting from the swing feed processing method,taking the most widely used paraboloid as an example,the machining mechanism is studied,the hardware system between the UMAC and the piezoelectric servo tool is set up,the PLC program is programmed,and the processing parameters of the aspherical surface are studied.The effect on the surface quality of aspheric surfaces provides theoretical guidance for subsequent process experiments.From the derivation of parabolic theory and the calculation of data,the establishment of numerical control system and the preparation of PLC program and the design and verification of aspherical orthogonal experiment are carried out in three aspects.First,the parameters related to aspheric surface machining are calculated,the trajectory equation of the center point of the tool nose is determined,and the asphericity between the paraboloid and the closest spherical surface is calculated.The connection between the asphericity and the pendulum axis angle in the polar coordinate system.Secondly,based on the IPC and UMAC motion controller,the communication and control between the piezoelectric servo tool and the UMAC in the aspherical machining CNC system are built.Industrial PC as a host computer to complete non-real-time tasks,UMAC controller as a lower computer to complete real-time tasks.At the same time,prepare a parabolic machining program that implements aspherical feed.Finally,an ideal roughness model based on a swing arm type machine tool is established.According to the roughness model,the spindle speed of the swing arm type machine tool,the pendulum arm swing speed,and the back knife amount are selected,and then the workpiece is made of a small diameter.Orthogonal experiments were conducted to select the optimal solution.Finally,an optimal solution was used toperform processing experiments on large-diameter workpieces to obtain an ideal paraboloid.