Finite Element Analysis And Structure Optimization Of The Whole CNC Milling Machine Tool

With the deepening of the process of China’s industrialization,making the demand for high-precise and high-efficient CNC machine tools goes up.Because the design methods of the traditional experience and analogy have been unable to meet requirements of the development of the modern manufacturing,using the optimization design method based on the more scientific theory for high-grade CNC machine tools has become the top priority.With a certain type of the CNC milling machine tool as the research object,this article used the methods of the modern design and analysis in the design phase of the machine tool which can carry out the comprehensive analysis of the static and dynamic characteristics for the structure of the machine tool.And using the modern optimization algorithms and softwares analyzed and optimized the structure for the parts and components of the machine tool.Applying the three-dimensional modeling software SolidWorks built the three-dimensional mathematical model for the XK719 CNC milling machine tool.On the basis of the 3D structure design, the finite element analysis software built the finite element modeling for the key components and the whole machine of the XK719 CNC machine tools.And the structure of the key components and the whole machine were carried out the static analysis,modal analysis and harmonious response analysis.Using the results of the analysis verified the static stiffness,strength and dynamic characteristics of the machine tool structure.This methods can find the weak links of initial design scheme of machine tool structure and can provide a scientific proof for the structure optimization design of the machine tool.This paper adopted two kinds of the optimization strategies for the machine tool.The first method used the optimization module of the software packages to find out the design variables of the high sensitivity values which greatly affect the structural characteristics through the sensitivity analysis with the structural mass and 1、2 order frequency as the object function and the structural wall thickness as design variables.And then the structural size optimization was carried out.The second method firstly adopted the method of the latin hypercube sampling to achieve sampling points on the basis of the mathematical statistics and experimental design.Then adopting moving least squares method fitted the sample points to obtain the approximate function.Finally,the adaptive response surface method was carried out to achieve optimum dimensions for the approximate function.The characteristics and results of the two methods were reviewed and the second method was choosed as the results of this research.Under the condition of little change in mass,the firstorder natural frequency was increased by 16.3% and the second order natural frequency was increased by 13% which indicated that the dynamic stiffness of the machine was improved.The research work of the finite element analysis and the structural optimization for XK719 CNC machine tool showed that in the design phase of the machine tool,using the modern design analysis and optimization method can effectively improve the static and dynamic characteristics of the machine tool which can also provide a scientific proof for the structural optimization design of the machine tool.