The Simulation Optimization Research Of Backward Extrusion Process On Deep Cylindric Part With Variable Thickness

Rapid rise of the cost of raw material promotes the enterprise to maximally reduce the weight of raw material. In the manufacture of aluminum aerosol cans, many enterprises strive to reduce the weight of single can, improve material utilization, reduce production cost, in order to achieve the profits improvement. So the cans with variable thickness is born, which is producted through only once backward extrusion. It is a newly environmental product which can save approximately 14% material compared to the uniform aerosol cans. The study of the extrusion parts with thin variable thickness is less, so this paper has carried out some research based on the realization of variable thickness. The main research contents are as follows:1. Combined with plastic forming principle, metal flow condition, forming mechanics, friction and lubrication of the blank on backward extrusion,process was analyzed.2. Thorough deep study of backward extrusion forming process on the deep cylindric part with variable thickness, considering to change the shape and size of die mold cavity to realize the change of it. Thus this paper devoloped the punch-die and intensive billet.3. The theory of Rigid-Plastie FEM on backward extrusion has been studied, some key technical problems for completing the FEM simulation have been proposed. Using Deform-3D to simulate entire backward extrusion forming process of the part with variable thickness, and reveal the extrusion forming mechanism of variable thickness.4. Distortion cause of metal and control method on the backward extrusion of parts with variable thickness were analyzed and simulated, it revealed the influence for distortion by the punch concession and die cavity curve. Through simulation analysis, the metal deformation law has been revealed, including stroke-load curve, veloeity field, equivalent stress field, volume reduction, then select the most optimal dies cavity curve.5. This paper further analyzed the influence for forming load and mouth distortion by so many technological parameters such as length of die bearing, friction factor, extrusion speed, length of variable cavity wall. Chose the most suitable process parameters to simulate once again ,which analyzed the metal flow condition; stress and strain and quality of wall thickness. Based on the optimization of process parameters, design punch-die structure.