| The construction of equipment manufacturing industry has now been transformed into the main body of China’s national economy,In the manufacturing industry,most products are processed and produced by CNC machine tools,the application of highperformance machining center is more and more extensive,mainly for the processing demand of domestic high-end products and precision machinery and other fields.The research shows that the thermal error of CNC machine tool accounts for a large part of the total error.And the change of thermal characteristics is the key decisive factor of machining accuracy of CNC machine tools,therefore,it is very important to analyze the thermal characteristics of CNC machine tools,one of the effective measures to improve the machining accuracy of machine tools is to reduce the error caused by heat in the process of machining.In this paper,the vertical machining center M4.5 produced by Shenyang Machine Tool Group is taken as the research object,and the theoretical mathematical model of thermal characteristics is established,theoretical analysis of temperature rise and thermal deformation of the main shaft system and key components of the whole machine using finite element analysis software ANSYS.Experiment on temperature rise and thermal deformation of M4.5 spindle system of vertical machining center.Finally,on the basis of ensuring the structure performance,the structure optimization of the spindle box is carried out.This paper mainly studies the following contents.(1)Through consulting a large number of documents,we know the research status of the thermal characteristics of machining centers at home and abroad,and analyze the thermal resistance of the joint surface.Based on thermodynamics,the thermal force coupling method is used for finite element analysis to determine the research content and method ideas of this subject,and provide clear direction for the follow-up research of the thermal characteristics of machining centers.(2)The theoretical mathematical model is established based on the mechanism of thermal deformation,and the analysis is made according to the structure of M4.5.The three-dimensional model of machining center is established by CATIA software,and the properties and materials are defined.Using the finite element correlation analysis software,the grid is used to establish the finite element model of the spindle system.(3)Establishing the temperature field of the spindle system and the finite element model of thermal deformation based on experimental conditions and boundary conditions,obtain a simulation analysis diagram of the temperature field and thermal deformation of the spindle system.At the same time,analyze the influence of the spindle system on the key components of the whole machine in the process of temperature rise,and the change trend of temperature and thermal deformation is summarized.(4)Using high precision magnetic temperature sensor and spindle rotation error analyzer to analyze the thermal state of spindle system experiment.Through the effective arrangement of the sensor,the temperature change of the spindle and the thermal displacement change of each sensitive point within 4 hours of no-load operation are effectively measured.Finally,combining theoretical analysis with experiment,size optimization is carried out for the parts of the system that have little influence on the structure,so as to reduce the influence of thermal error on the accuracy of machining center. |
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