Simulation And Optimization Of The Stamping-forging Hybrid Forming For Miniature Aluminum Alloy Bearing Block

The stamping-forging hybrid forming is a new process for non-uniform thickness sheet, which is combined of the sheet forming and the bulk forming. It can substitute for many traditional processes such as casting, welding, cutting and so on, for both having the advantages of sheet forming—big distortion area—and bulk forming—non-uniform thickness, and not only raise the production efficiency, but also improve mechanical property of work piece. In view of certain type of miniature bearing block, the stamping-forging compound forming process was used, the forming rules of essential location were studied, and the combination plan of optimal process parameters was gained through optimization in this article.Firstly, the extrusion process was chosen to form the small columns on flange through the process analysis of the miniature bearing block, and the feasibility of the method was confirmed by analyzing the flowing rules of material during forming. Secondly, in order to avoid the influence between two connectional stations the combined blanking and extrusion process was taken into consideration to form the cylinder-shaped location. The numerical simulation analysis of the forming process was carried on to obtain some forming rule with the help of the professional finite element software DEFORM. The result indicates that the deformation zone of metal materials is located under the punch during the combined blanking and extrusion process, and below the binder board only the elastic deformation takes place which does not have the influence on the formed shape of the previous step.After analyzing the rules of material deformation during the combined blanking and extrusion forming process in general, the method combining numerical simulation and orthogonal design was selected to analyze the effects of the three key parameters such as friction coefficient, the force of counter-punch and BHF towards the damage. The sensitivity of index arm on processing parameters was estimated by range analysis. The result shows that friction coefficient is the main influential factor to the damage, the force of counter-punch is medium one, and BHF is the smallest one. Based on the consequence of the orthogonal design, the damage was chosen as the optimized goal, and the genetic algorithm combined with artificial neural networks was taken to optimize the processing parameters. The optimized result indicates that after the optimization the processing parameters can obtain the lowest damage value, so enhance the forming property of material enormously, and the quality of work piece obtained correspondingly is optimal as well.Finally, the fine blanking process was used to form the final shape of the work piece and the simulation of the process was carried on to obtain the reasonable processing parameters for producing a satisfied work piece. Meanwhile, the germination and the expansion of crack during fine blanking process in different fracture criterion were discussed through fine blanking simulations to obtain the influence law of stress triaxiality on fine blanking crack and to provide the essential basis in choosing an appropriate fracture criterion for simulating the fracture process effectively. The result indicates that the smaller the stress triaxiality is, the later the crack germinates; while the tooth ring with tooth profile can enhance the hydrostatic stress and cut down the stress triaxiality. The simulation of germination and the development of the crack in thin steel sheet fine blanking with the N-CL model are more coincided with the practicality.The results of this research have the instruction function to the practical production.