The Machining Accaurcay Of Machine Tool Influenced By Foundation Uneven Settlement

High precision machine tool is an important basis for machining high precision workpiece, and the heavy duty of high precision machine tool itself is very big, will have a lot of force on the basis, with the time accumulated to cause the foundation deformation, and the foundation deformation will affect the machine tool, if the machine tool has deformed, it is difficult to guarantee the machining accuracy of the machine tool, therefore, it is necessary to study the influence of machine tools and foundation, especially for the heavy-duty machine tools which have higher machining accuracy request. Based on creep theory of concrete, the equivalent elastic modulus of concrete is calculated by selecting appropriate concrete creep experience, using the finite element analysis software, the deformation of the foundation is analyzed, under different equivalent elastic moduli. The deformation curves of the foundation with the time under the weight of the machine tool are obtained, and the feasibility of the method is verified by experiments. The equivalent model of machine tool is established, and the frame structure of the beam element is simplified as the gantry machine tool, and the deformation of the machine tool is calculated by the path following method of nonlinear finite element method.The research object of this paper is the heavy-duty gantry type machine tool. The foundation deformation caused by the weight of the machine tool is studied, and the influence of deformation on the machine tool is analyzed. In this paper, the various theories and the empirical formulas of creep calculation of concrete are described; combined with finite element software workbench to analyze the basic deformation, according to the calculation results and actual measurement data, the data can be selected to meet the changing rules; by comparison of various nonlinear finite element method, the characteristics of load control, displacement control method and arc length method are analyzed, and a suitable path following method is chosen to solve the deformation of machine tool.According to the results obtained, the foundation is relatively fast in the initial stage, and it can make the prepressing plan and eliminate the deformation of the initial foundation, and adjust the accuracy of the machine tool according to the deformation law. At the same time, according to the nonlinear finite element analysis of the deformation of the machine tool, the structure of the machine tool is strengthened to reduce the influence of basic deformation on machine tools according to the large deformation.