Research On Thermal Deformation Monitoring And Compensation Method For Rotational Symmetry Surface Milling Process

In the machining industry,thermal errors are a common problem that can lead to inaccurate accuracy and dimensional deviations in the final product.With the advancement of CNC technology,five-axis linkage CNC machining centers have become more and more popular in various industries in recent years.Compared with three-axis machines,five-axis machines have three linear axes and two rotary axes,which can machine parts from multiple angles to perform more complex machining operations.However,its complex geometry and large number of components make it more susceptible to thermal errors.In this paper,a double turntable five-axis machine tool is taken as the research object,and the impeller is selected as the workpiece for research.The optimization goal is to improve the processing quality of complex curved surfaces,and the optimization research is carried out in combination with support vector regression and machine tool kinematics.The main research contents of this paper are as follows:Firstly,the process parameters of the milling impeller and the composition of the experimental test platform are introduced,and the method and steps of thermal error compensation are systematically described.On the basis of the impeller simulation processing,the movement of the machine tool and the location of the main hot spots in the milling process are analyzed.Considering the timeliness requirements of the data in the experimental analysis,this paper reasonably arranges the location of the measuring instrument and designs the corresponding processing experiment method.Secondly,mathematical modeling is carried out on the thermal errors in the machining process of the machine tool.In this process,we used the correlation coefficient between temperature and offset as a standard,and used correlation analysis to screen out the key temperature points in the process of machine tool processing.On this basis,according to the key temperature points,we use the support vector regression algorithm to establish a thermal error compensation model,which can perform accurate thermal error compensation according to the selected key temperature points.Through the verification of the model accuracy,the validity and accuracy of the model are proved,and the offset generated in the machining process of the machine tool can be accurately predicted.Again,a thermal error compensation method based on five-axis machine tool milling is proposed.Through the real-time collection of key temperature point data,the thermal error model is used to predict the thermal error of the machine tool,and the geometric error is converted into spatial error based on the principle of kinematics,so that get the compensation value.Write the integrated upper computer software according to the communication requirements of the machine tool.The software will be responsible for collecting temperature data,calculating the thermal error offset,and establishing communication with the machine tool for error compensation.Finally,the compensation system is used in actual processing for experimental verification.The experimental process includes the entire finishing process of the impeller.The compensation value is obtained through real-time measurement of key temperature points and then communicates with the machine tool to complete the compensation of the machine tool.The impeller blades before and after optimization were analyzed using a threecoordinate measuring instrument.The experimental results show that the impeller milled by the machine tool after introducing thermal error compensation has a surface profile value deviation of less than 0.1m and a more uniform distribution of deviations at various positions on the blade surface,which proves that the thermal error compensation scheme is feasible.