The Design And Experimental Research Of CNC Machining Center Spindle Temperature Rise Test System

With the rapid development of the modern machinery manufacturing technology,the requirements for machining precision and stability of CNC machine are also becoming higher and higher.CNC machine as machining machine tools of modern manufacturing industry has been the pillar of the national economy,and become an important symbol of the national comprehensive strength and industrial modernization level.Numerous studies show that thermal error,accounting for about 40%to 70%of the total error of the spindle system,is the maximum error source of CNC machine tools.As a key component of CNC machine tools,the thermal deformation of the spindle system is caused by an error which accounts for 60%to 80%of the total process error.Thus,reducing the thermal errors of the spindle system is essential for improving the accuracy of CNC machine tools.How to obtain the thermal characteristics of the spindle system quickly and accurately has become a hot issue in the field of the thermal characteristics of CNC machine tools.Based on the related research of the thermal characteristics of CNC machine tool spindle system.The temperature field simulation model of spindle system is established.The accuracy and authenticity of the model are verified through the temperature experiments of the spindle system.The model of the temperature field of spindle system is optimized by the neural network RBF.The temperature change of the spindle system is obtained accurately.The main contents are as follows:In the chapter 1,the purpose and significance for the analysis of thermal characteristics of CNC machine tool spindle system are introduced.The contents of the thesis are proposed based on the current disadvantages of the research analysis.In the chapter 2,the basic structure of the 170CP06 mechanical precision lathe spindle system is described.The basic pattern of heat transfer and the basic theory of thermal characteristics are introduced.The three-dimensional solid model of the mechanical spindle system is established by using 3D software SolidWorks and imported into the finite element analysis software ANSYS for the heat analysis.In the chapter 3,based on the analysis of the heat source and boundary conditions of CNC machine tool spindle system,the finite element analysis model for calculating the steady-state and transient temperature field of the spindle system are established for obtaining temperature distribution and thermal equilibrium time of the spindle system.According to the requirements of the subject,the test platform of mechanical spindle is designed and the related testing software is developed.The temperature testing requirements is met and the purpose of the experiment is achieved.The temperature rise of the spindle system under unload and load conditions can be measured by the developed test system and the loss of power of the spindle system under unload conditions.The influence of spindle speed and spindle load on the temperature rise of the spindle system under unload or load conditions is analyzed.The temperature rise of the spindle system obtained by the simulation model is compared with the experimental data to verify the accuracy of the model.In the chapter 5,in order to obtain the temperature distribution of CNC machine tool spindle system more accurately and quickly,a optimization model for calculating the heat transfer coefficient based on RBF neural network is proposed.According to experimental data,the convective heat transfer coefficient is optimized.The optimization solution is substituted into the finite element model for analyzing again a new temperature field distribution.The obtained temperature rise results are compared with the experimental data again,and the error for both of them is reduced,which shows that the optimization model is verified effectively.Therefore,the temperature change at any point of the spindle system at any time can be obtained by the finite element model and the optimized heat transfer coefficient.In the chapter 6,the main research work and innovative achievements are summarized,and the further research is proposed.