SGM50A Horizontal Machining Center Key Structural Analysis And Dynamic Structure Optimization

With the performance requirements of speed and precision for upscale CNC (Computer Numerical Control) machine tools improving, controlling the dynamic response of structure has become the key problem in the process of machine tools’development, and conducting structure analysis and optimization using FEM (Finite Element Method) is an important method and inevitable trend of resolving this problem. In this dissertation, structural analysis and dynamic optimization was conducted for the bed, column and assemblies of these two components, which are from the SGM50A precision horizontal machining center, based on FEM.Firstly, the finite element models of column and bed were established using shell element and body-shell mixed element respectively in preprocessing software HyperMesh, and the finite element model of assemblies was also established through flexible connection of bed and column with spring-damping element method. Aiming at finding out the characteristics of stress distribution and modal as well as weaknesses of the structure, the static and modal analysis was conducted. In addition, the effect of the variation of connecting stiffness between bed and the column on modal characteristics of the assemblies was studied. It’s proved that when the real connecting stiffness varied in the range of±20%of theoretical value, the calculation error caused by it the can be ignored.Secondly, hammering modal test was carried out on the components, and the test results proved the correctness of finite element models. The theoretical error was calculated by comparing the modal frequencies, which are in the same modal shape, from theory calculation and the experiment respectively. In addition, the main reasons lead to theoretical error and the omission of experimental modal were concluded.Finally, considering the mechanical analysis results and requirements of the subject, the optimization goals were proposed, and the column optimization scheme given reduced its weight by10.7%and increased its modal frequencies in excitation band by an average of7%under the premise of keeping the static stiffness to meet the requirements, which achieves the desired optimization objective.In this dissertation, the structural mechanics analysis of key parts of SGM50A were accomplished based on FEM, and optimization scheme of column was also proposed. It provide a reference for improvements of the machine tools, meanwhile, the method of structural modeling and optimization used in this paper has a certain reference value.