Thermal Error Measurement And Analysis Of Vertical Machining Center

High precision,high efficiency,high stability,intelligent digitalization,high efficiency and low consumption have become the development direction of CNC machine tools.The research shows that thermal error is one of the most important factors affecting the machining accuracy of machine tools.It has great significance that the effective measures were taken to reduce or compensate for the influence of thermal error for the development and innovation of manufacturing technology.Because of its high flexibility and applicability,machining centers are mainly applied to work pieces with complex shape,many processes,long cycle and high precision requirements.Taking ZH-850 E vertical machining center developed by Shandong Excellent Guanhong limited company as the research object.Aiming at the influence of thermal errors on the machining accuracy of machining centers,the measurement and analysis methods of thermal errors are optimized,and the mathematical model for predicting thermal errors of vertical machining centers is established,the useful basis for the realization of thermal error compensation it is provided.The main research works have been done as follows:(1)Applying numerical analysis method and ANSYS Workbench finite element analysis software,the finite element model of vertical machining center is established,the steady and transient temperature fields and thermal deformation fields are analyzed.The variation law of temperature and thermal deformation was obtained,and the design guidance suggestions were put forward to reduce the thermal deformation of the machining center.(2)According to the typical working conditions of the machining center,and the measurement experiment of the temperature and thermal error for the machining center is designed.Through analyzing the experimental data of temperature and thermal error,the influence of machining center temperature rise on thermal error is explored.When the trend of thermal error is closed to the temperature change,and the machining center is reached to the thermal balance,the thermal error is tended to stable.The high correlation and good correspondence between temperature and thermal error are proved in the results.(3)By using the method of fuzzy clustering analysis and complex correlation coefficient analysis,the key temperature measurement points for thermal error modeling are optimized.The optimal regression parameters of the model are matched by the theory of multiple linear regressions and least squares,the mathematical model for predicting thermal errors is established,and the accuracy of the model is verified.The results show that the thermal error mathematic model has high accuracy,low dispersion and stability of residual error,and can be applied to thermal error compensation.