Static And Dynamic Characteristics Analysis And Key Structure Optimization Of Turn-milling Complex Machining

The development level of machine tool reflect the level of a country's manufacturing industry.In recent years,people have more and more demand on machining accuracy of CNC machine tools,there are many factors that affect the accuracy of machine tools,static and dynamic characteristics of CNC machine tools are two of the important factors.The modeling of the joint has an important influence on the accuracy of the dynamic characteristics analysis of whole machine.In order to obtain high accuracy,high speed and high-efficiency CNC machine tools,advanced CAD/CAE technology is needed to design,optimize and analyze the machine tools.By improving the performance of the machine tools,the design cycle is abridged and the cost of production is reduced.In this thesis,it takes turn-milling complex machine tool as the object of study in this paper.The 3D model of the whole machine are created by using Solidworks.The static and dynamic characteristics of the machine are analyzed by using ANSYS Workbench.Through the weak link identification,the key part to affect the static and dynamic performance of the machine tool are optimized.The main research contents include the following:Firstly,the finite element model of the whole machine is built in ANSYS Workbench,The stress,displacement and cloud figure of the whole machine under different working conditions of Z axis and self-weight are analyzed.By calculating,the force of the machine tool in turning and milling is obtained.Then the stress and displacement deformation of the machine tool under the simultaneous action of gravity and turning force as well as gravity and milling force are analyzed.Secondly,based on joint surface characteristics,the dynamic characteristic parameters of the combined interfaces of TMS-200 s turn-milling complex machine tool are got based on Masataka Yoshimura method,and the parameters are added to the joints in the form of spring-damper elements to establish the equivalent dynamic model.And then,and the first six natural frequencies and harmonic response curves of the whole machine are obtained through the modal and harmonic response analysis of the whole machine.The results illustrate that the column structure is the key part to affect the dynamic performance of the machine tool.Finally,a mathematical model was built by taking the first order modal frequencies,the mass and the effective static deformation of the column as the objectivefunctions and the thickness of stiffener plates on both sides of column as the design variables,which determined the optimal set of size parameters are gotten by response surface methodology.Finite element analysis results demonstrate that the mass of the optimized column is reduced by 12.37%,the top 6 nature frequencies of the machine tool are increased with different degrees,and from harmonic response analysis results of the machine tool,the response amplitude has been appreciable decreased in every directions.The design method of this paper effectively improves the dynamic performance of the machine tool.