Dynamical Parameterized Modeling Of Fixed Joints In Machine Tools

Modern machine tools are moving in the direction of high speed, high precision and integrated, so the dynamic characteristics of machine tools will directly influence the processing characteristics. A lot of studies have shown that the joints of machine tools have a significant influence on the dynamic behavior of machine tools. Therefore, in order to predict and improve the general system performance of machine tools and make optimized design of machine tools, the research of the dynamic characteristics in machine tools must be studied.So far, the researches of joints modeling and parameter identification have made a lot of achievements, but there are no in-depth on the research of factors influencing the joints dynamical parameters. The author investigate the XHK5140, 7-axis five linkage machine tool and the machine of Beijing mechanical and electrical research institute. A series of models of joints connected with two bolts are designed, which contains major factors (surface roughness, pre-load, size).LMS Test.Lab vibration Test and analysis system is used to do modal experiments. Based on the parameter identification method of theoretical modeling, the dynamic parameters (mainly refers to the dynamic stiffness) of joints are identified. And then, through analysing the stiffness matrixes of joints in various working conditions, the article presents the power function model between the dynamic stiffness and preload, and verifies the model. Through the orthogonal experiment, the article analyses various factors influencing the dynamic stiffness of joints. Through comprehensive experiments, based on the response surface method (RSM), the surface parameterization statistical model of joints is put forward, and then the article designs the parametric database management GUI software of joints. In the end, through experiments on the specimen of single joint elment and multiple joint elements, through DMIG cards and parametric statistical model, the stiffness matrixes which are calculated are put into MSC. FEA, and the dynamic parametric modelof joints is verified. Through a lot of experiments, the dynamic parametric model is put forward and verified. Based on the model, dynamic stiffness of joints in varies working conditions can be calculated. The dynamic characteristics of joints connected with bolts in machine tools can be simulated, so that the cost of experiments can be saved.