Error Transfer Analysis Of Machine Tools' Supporting Component And Structure Design

The development of mechanical industry and the consumption of natural resource has created the need to the higher requirement of the machine tool. High precision and light weight is becoming an inevitable trend in the machine tool industry. The machine tool's supporting system, which is composed of multi-supporting parts in the sequence, has the function of transmitting forces and the movement. The transfer errors between supporting parts will lead to the errors of the supporting system, which have an effect on the machine precision of machine tools. So it is essential to analyze the motion transfer errors and the position transfer errors to build the error model of the supporting system. This article is aimed to research on the error transfer law and build the error model of the supporting system considering rail's geometrical errors and the supporting parts'elastic deformation to complete the contribution analysis. At last, the structural optimal design of the column is done. The main research contents have several aspects as follows:(1) The background and purpose of this research is explained. Research on the error characteristics of the rolling guide pair, synthesis error modeling in machine tool and structural design of supporting parts are reviewed, respectively. Moreover, it briefly summarized the research achievement of machine tool design.(2) The motion error transfer of the supporting component is analyzed. At first, the error sources of the supporting component are researched and the description of motion errors is given. The motion error transfer model of the component is built with motion errors equivalent method and the solution of static equilibrium equations. And the influence of rails' geometrical errors on motion errors is researched.(3) The position error transfer of the supporting component is analyzed. The supporting parts'elastic deformation will lead to the position error of the joint face between the supporting component, which causes the adjacent part's position and pose error. At first, the machine tool'static characteristics is analyzed by means of the finite element to ensure the elastic deformation nephograms of the supporting parts. A position error evaluation method of the joint face is put forward to complete the analysis of the position error transfer of the supporting component with extracting the displacement parameters of the key points in the supporting part's joint face.(4) Based on the analysis of the supporting component's error transfer, with multi-body system theory, the relationship between rolling guides' geometrical errors and the motion error transformation matrix, supporting part's elastic deformation and the position error transformation matrix is established, respectively. The motion errors of rolling guides in the direction of X and Y and the supporting parts' elastic deformation is calculated to analyze the influence of rolling guides' geometrical errors and the deformation on the error of the supporting system and get the contribution rates,41% and 59% respectively.(5) With the contribution rate analysis of all the parts' elastic deformation, the column is the weakest factor of the rigidity in machine tool. The new structure scheme of the column is obtained through the process of physical modeling, conception model design and structure scheme design. The comparison of performance in the original and new column has been made and the results show that the sensitive error of the supporting system is decreased by about 15% and the weight loss of the new column is 0.54%.