Analysis Of The Dynamic Characteristic Of The Five-axis Machine Tool With Double Turntable

This paper takes Tuopu VMC-C50 dual-turntable five-axis machine tool as the research object to study the dynamic characteristics of the whole machine tool.At the same time,it conducts in-depth research on the dynamic characteristics of the dual-turntable rotary table among the important parts of the machine tool.First,study the dynamic characteristics of the machine machine,the stiffness of each joint surface of the machine tool was first analyzed,and then the geometric model of the two-turn five-axis machine tool was established.The model was imported into the finite element software and set according to the real machine tool material and the calculated stiffness parameters.The whole machine modal at a fixed position is obtained by analysis,and the machine modal at 27×3 working positions is simulated and analyzed.A three-dimensional kriging space prediction model for a dual-turntable five-axis machine tool is established.Based on the three-dimensional Kriging prediction model,the natural frequencies of the system in different processing spaces of a dual-turntable five-axis machine tool are analyzed.The results show that with the change of the swing angle of the pendulum,the natural frequency of the system in the machining space of the dual-turntable five-axis machine tool ranges from 45.3 Hz to 53.4 Hz,and the natural frequency of the system is the smallest when the swing angle of the pendulum is 0°.Secondly,the dynamic characteristics of the machine tool rotary workbench are analyzed,the article analyzes the dynamic characteristics of the rotary table of the machine tool,discusses the axial vibration of the table caused by the change of the torque and load on the table,and establishes it based on the elasticity of the plate and shell.The non-linear dynamic equation of the axial vibration of the machine tool table when the table is subjected to torque,swing moment and load;then the dynamic displacement in the axial direction of the table is solved according to the Galerkin truncation method,as well as the bifurcation diagram and displacement of the processing system Waveform diagram,phase plane trajectory and Poincarécross-section diagram,etc.;finally analyzed the influence of table torque,swing moment and load changes on the axial vibration of the table during processing.The study found that with the change of external load,the axial vibration of the worktable is mainly in the state of large periodic motion,the maximum amplitude is 0.09 mm,and the change of external load has the greatest influence on the axial vibration of the worktable;the axial vibration of the worktable is changed with the swing moment.Mainly the chaotic state of small period and small area,the maximum amplitude is0.03 mm,the swing moment has little effect on the axial vibration of the worktable.Modal experiments verify that the difference between the simulation value of the first five-order natural frequency of the machine tool and the experimental value is within 20%.At the same time,experiments are carried out on the influence of torque and load changes on the vibration characteristics of the machine tool table during table processing,and it is proved that the error between the experimental value and the analysis value of the non-linear analysis of the table axial vibration of the dual-turn five-axis machine tool is 12.3%.By studying the dynamic characteristics of the machine machine and workbench,it can provide technical support for machine tool working path planning and workbench stability control during workpiece machining.