Analysis Of Thermal Deformation Affected By Internal Heat Source In Vertical Machining Center

With the rapid development of science and technology,the requirement for the machining accuracy of vertical machining centers is getting higher and higher.At present,the most important factor affecting the machining accuracy is the thermal deformation caused by temperature rise,it is necessary to analyze.In this paper,a certain vertical machining center is used as a model through theoretical analysis,finite element simulation and experimental verification.The main research contents are as follows:The finite element model of the spindle system is established,and the finite element software is used to simulate the temperature field,the thermal-structural coupling analysis and the transient static analysis,the model of the spindle system is analyzed.The influence of thermal error on the feed transmission system of ball screw is studied.The heat sources of the feed system of ball screw are analyzed.Comparing the temperature field distribution of the finite element simulation of the ball screw with or without thermal contact resistance,the relationship between thermal contact resistance and the temperature field is studied.The steady-state thermal analysis,transient thermal analysis and thermal-structural coupling analysis of the feed system of ball screw are carried out by using ANSYS finite element software.According to the heat transfer equation,the initial and boundary conditions of the ball screw are analyzed,and the analytical equation of the temperature field of the ball screw is solved.Combined with the theory of thermal deformation,the temperature field model is used to analyze the axial thermal elongation error caused by the X,Y direction screw being heated.The temperature field prediction model and thermal error model are validated by experiments.In the experiment,the thermal error of X and Y direction of the spindle is measured indirectly by the center point deviation of the spindle which can be measured directly in the process of processing.The buttord algorithm is used to filter the experimental data and draw the track map of the center point of spindle.Using the finite element simulation data,the center point deviation of the spindle is obtained and the deviation of the spindle is processed and the deviation curve of the central point of the spindle is obtained.