Research On Fine Blanking Process Of Crank And Optimization Of Die Structure

The traditional fine blanking process is carried out on special triple-action press. However, general enterprises are unable to buy fine blanking presses because of the high price. As a result, the application of fine blanking technology will be restricted only by the increase of fine blanking presses. Therefore, it is an important way to make this technology more and more popular by the development of fine blanking process on common press.Two main conditions for the implementation of fine blanking, three-dimensional compressive stress and small clearance, were obtained by the analysis of fine blanking principle and comparison of fine blanking and conventional blanking. The necessary technological measures for fine blanking on common press were presented, and the feasibility of fine blanking on common press was demonstrated. Furthermore, the solution to fine blanking on common press was presented by die deigned with nitrogen gas springs. The blank is in the state of three-dimensional compressive stress with the help of nitrogen gas springs, and it makes the process of fine blanking on common press available.The numerical simulation for bending process of crank was carried out by the FE software DEFORM-3D. The process scheme and the die structure were designed with the help of simulation results. Parts of different sizes could be formed in one bending die with the optimization of die structure, as a result, the production efficiency is improved and the production cost is reduced.The numerical simulation for fine blanking process of circular hole is carried out by the FE software DEFORM-2D. The conditions with or without counter pressure were discussed respectively. The material flow, distribution of hydrostatic pressure, effective stress, effective strain and load of punch were analyzed. Furthermore, the quality of cut surface was predicted by using Oyane ductile fracture model.The research method of FE simulation combined with process test is used. The process tests of fine blanking were carried out, and the dimensional precision and quality of cut surface were analyzed. It is shown that the results of simulation and process test are consistent.The result shows that fine blanking on common press is available by die designed with nitrogen gas springs, which can provide blank holder force and counterpunch force. It is shown that fine blanking parts with high dimensional precision and good cut surface can be obtained with this method.