Numerical Simulation Of Aluminum Alloy Extrusion And Optimization Of Mold Structure

Aluminum alloy has the advantages of high specific strength, excellent corrosion resistant property, non-magnetic, high heat and conductivity, good sealing, easy recovery, therefore it has been widely used in construction, machinery manufacturing, household appliances, vehicles, ships, aircraft, communications and other fields. The method of extrusion processing to product aluminum profiles has advantage of saving metal and high production efficiency. In the extrusion process, the interior mold is sealed. So it is difficult to control the material flowing, the stress field, the strain field and the loading condition. At the same time, as the key point, extrusion production of mold design often depends on the experience to modify the mold with the experimental mold to carry on repeatedly and it often creates the waste manpower physical resource. In order to improve the extrusion product quality and enhance the mold rated capacity, this paper uses finite element simulation software DEFORM to carry out the aluminum extrusion process simulation, for confirming the effect of optimized extrusion mold.The paper elaborates the domestic and foreign research progress on extrusion mold optimizing design and the metal plasticity formation simulation technology. It expounds fundamental theories for simulation of metal forming processes with finite element method, including the basic supposition of plastic flow theory, variational principle of rigid-plastic finite element method and elastic-plastic constitutive relation. Simultaneously, it also introduces the technical characteristic and the main function of finite element computation software DEFORM and explains the establishment of analog computation model process in DEFORM Pre-processor.The paper has designed the new extrusion mold including the traditional chamfer optimization, multiple steps, different angle, different vertical parameter and horizontal parameter optimization. The established analog modeling in DEFORM is used to analog computation. The result of stress field, strain field, load curve and so on was obtained. Based on analysis of the mold geometry parameter and the simulation result, the conclusions are as follows:(1) Optimization with chamfer changes the material flow, stress and strain situation. The chamfer reduces the extrusion load and homogenizes the material flow in extrusion process. (2) Choosing appropriate parameters of step and angle, can effectively improve the extrusion process. In extrusion process with multiple steps die, material flowing through one step is similar to extrude one time, and multiple steps make the whole extrusion process be equivalent to multiple-extruding. Angle of step makes the material flow more smoothly. A combination of angle and multiple steps, can significantly increase the strain, and also can ameliorate the axial hole defect.(3) As the feeder plate angle becomes larger, the load will get smaller. However, when feeder plate number increases, the load changes higher. The increased load partly compensates the friction and partly compensates the deformation resistance due to shear deformation in vertical direction.(4) Different vertical direction and horizontal direction parameters in die design, affect the extrusion situation in a certain degree. The increasing of step vertical height can add the effective stain and effective stress. And the influence of step width is very small.