Modal Analysis And Optimization Of Spindle Box Of Gantry Machining Center Based On ANSYS

PM1220HA machine tool is a high-speed gantry machining center that is widely used in industrial production in China.Based on the structural characteristics and design ideas of PM1220 HA,this paper develops a power with a speed of up to 18,000~20,000 rpm based on the application requirements in actual work.The spindle high-speed gantry machining center is mainly used in the field of high-speed machining,and has the characteristics of high flexibility,high precision and high stability.Since high-speed machining puts very high demands on the static and dynamic characteristics of the machine tool,in order to verify the rationality of the machine design,and further realizing lightweight,in this paper,the spindle box of the high-speed gantry machining center is taken as the research object,detailed analysis of working state characteristics of spindle box components is carried out by using finite element analysis software ANSYS,including static analysis and modal characteristics analysis,OptiStruct software is used to optimize the structure.The static and dynamic characteristics of the spindle box before and after optimization were compared,and the vibration characteristics of the spindle box before and after optimization were compared by hammering experiment,the results show that,after structural optimization,the stiffness of the spindle box is increased by 1%-8%,the natural frequency of the structure is increased by 6%-18%,the total weight of the spindle box components is reduced by 45 KG,and the weight loss rate reaches 7.8%,it realizes lightweight,saves materials and costs,and improves economic benefits.Firstly,according to the actual situation of the machining center,the three-dimensional solid model of the spindle box is established by using the three-dimensional modeling software Pro-E.Secondly,the finite element analysis software ANSYS is used to carry out static analysis.The results show that the static characteristics are good.On this basis,modal analysis is carried out,and the first six natural frequencies and corresponding modal modes of the spindle box are obtained,by calculating and analyzing the working excitation frequencies and natural frequencies of the spindle box,it is determined that there will be no resonance in the structure,and the static and dynamic characteristics are good,which verifies the rationality of the design.Finally,in order to realize the lightweight of the spindle box of the machine tool,the optimum design of the spindle box is carried out by using OptiStruct software,and the effect of the optimum design is reflected.The static and dynamic characteristics of the optimized spindle box are analyzed and evaluated,and compared with those before optimization,the overall stiffness and natural frequency are improved,which ensures the stability of the machine tool under high-speed working conditions.This paper lays a foundation for further research on this kind of machine tools and other types of machine tools.