Dynamic Analysis And Structural Optimization Of Feeding System In Gantry Machining Center

Feeding system is an important part of CNC machine tools,feeding system is designed to meet specific conditions,so as to ensure that the feeding system has excellent static and dynamic performance,and ultimately to ensure that the CNC machine tool has geometry accuracy and machining precision.With the continuous development of CNC machine tools to high precision and high speed,the vibration of the feeding system becomes one of the important factors to improve the performance of the machining center and improve the machining precision.Therefore,the dynamic characteristics of the feeding system and structural optimization have been widely concerned by machine tool manufacturers and experts and scholars.In this paper,the virtual prototype of the feeding system is established by combining the experiment and simulation,and the dynamic characteristic analysis and structural optimization of the feeding system are carried out in combination with the"High speed five-axis gantry machining center",a major national science and technology project.The main work is as follows:Firstly,The kinetic virtual parameters of the feeding system are established,and the kinetic parameters are obtained by simulating the motion of the feeding system under different conditions.Ansys and Adams were used to create the dynamic virtual prototype model of the feeding system,and the natural frequency of the table X was obtained by using the harmonic response analysis.The dynamic analysis of the feeding system under the cutting and rapid feed conditions is carried out.The driving torque of the screw is obtained,and the matching of the feeding system is carried out.At the same time,the influence of the contact stiffness of the screw and the axial stiffness of the bearing and the mass of the table on the vibration frequency of the table are analyzed.Secondly,combined with the simulation model and the experimental test,the vibration characteristics of the feeding system are analyzed and studied,and the modal parameters are obtained.The test and analysis of the vibration response of the feeding system under the cutting excitation and the fast feed condition are completed by using the DH5922N signal acquisition and analysis system.The components of the forced and natural frequency vibration in the vibration acceleration signal of the table are found,Compared with the natural frequency obtained by the simulation,it can be proved that the virtual prototype is set up correctly.The modal test is designed and the modal test is completed.A finite element model of the feeding system is established.The modal analysis is carried out to obtain the first six modes of the feeding system and the frequency of the feeding system.To determine the weak parts of the feeding system and provide the basis for the optimization of the feeding system structure.Finally,the Workbench is used to optimize the structure and topology of the feeding system,and the dynamic characteristics of the feeding system are improved.The dimensions of the internal structure of the workbench are optimized and the natural frequency and rigidity of the workbench are improved without increasing the weight of the table.The influence of the axial stiffness on the vibration frequency of the table is analyzed by the difference between the screw nut and the bearing bearing at both ends of the screw.The topology of the ribs at the installation site of the bed bearing is optimized and the axial support stiffness of the screw bearing is improved.This study has a certain guiding significance for optimizing the feeding system of the gantry machining center and improving the static and dynamic performance of the machine tool,and thus improving the processing quality of the machine tool.