An Investigation On Structure Of Extrusion Die And Optimization Of Combined Dies About Support Shaft With Finite Element Method

With the development of mechanical industry and the competition among international manufactures, as an important ingredient of advanced manufacturing technology, net forming or near-net forming becomes highlight in recent years. The extrusion process as a branch of near-net forming has been emphasized in metal forming field because it has many advantages, such as energy and material saving, great power efficiency and high quality compared with the traditional manufacturing process. The support shaft with large size is an important force-bearing part of automobile components. In the past, this part mainly relies on the cutting manufacture. A new technology-extrusion was explored to improve the comprehensive performance of support-shaft. However, the life span of support-shaft's extrusion die was short due to the high temperature and high pressure the extrusion die worked in. How to improve the life of the extrusion die is a pressing problem. There are many factors which affect the life of die. In this paper, the problem was researched in perspectives of mechanical and metal forming respectively.With the fast development of computer hard and soft wares, finite element method (FEM) and computer graphics, the computer aided engineering technology based on numerical simulation are increasingly employed in metal forming field. The simulation of metal forming processes can be realized on the computer instead of test in work station. The results including lots of useful parameter derived by the technology of FEM could give more suggestions for production. In this paper, the combination of special software DEFORM and general software ANSYS provides a feasible way to analyze stress and to optimize the structure of combined dies.The FEM model of upsetting combined with extrusion process of the support shaft was established and the forming process was simulated by DEFORM software. The result of simulation about distribution of stress of female die with different displacement of male die shows that the female die had the maximum stress at the end of process, In this article, the simulation result of forming process in the end of process about distribution of stress inside of female die was exported as a boundary condition for structure analysis and optimization of female die in subsequent step with ANSYS. The method of the data propagate is more practical in contrast to uniform load acted on inside of female die with complex shape. According to the result of FE-simulation with ANSYS, the one layer die could not meet the requirement of die strength although the dimension of outer diameter was increased. Multi-layer combined dies was a solution to this problem. In this paper, a lots of simulation schemes which were described in different shrinkage and outer diameter dimension of shrinking-fitting ring were designed to analysis the distribution of stress of two-layer dies in uniform and non-uniform temperature field respectively. At the end of paper, the APDL language was developed to optimize the shrinkage and outer diameter dimension of shrinking-fitting ring for two-layer and three-layer die. The optimum parameters will support the design of die in the future.