Accurate trimming line optimization of multi-station progressive die for complex automotive structural parts

Abstract

The complex multi-station progressive die has many characteristics, such as many stations, complicated structure, and a strong correlation between stations. The trimming line is affected by the subsequent forming stations, which makes the accuracy of the trimming line very low and difficult to predict. Therefore, a new iterative optimization method of trimming line based on the strain path of material and the refined numerical simulation of the whole process was researched and proposed for multi-station progress dies of the complex automotive structural parts. The initial blank outline is unfolded by one-step and multi-step of the inverse finite element, respectively, to obtain higher accuracy trimming lines. The refined numerical simulation of the whole process based on the solid-shell element is utilized to verify the feasibility of the trimming lines, and the real parameters of the press, die surface, and process parameters are fully considered. The boundary nodes of the initial mesh of the blank are fitted according to the B-spline curve, and then the strain path and direction of the boundary node numerical simulation before and after are extracted. The iterative optimization of the trimming line is made by adjusting the B-spline curve, which can reduce the number of iterations and improve the edge quality of trimming inserting steels. The results of a complex example demonstrate that the newly proposed optimization method has an excellent performance and efficiency extremely in the trimming line optimization and numerical simulation.