Research On The Accurate Prediction Method Of3D Trimming Line

In sheet metal stamping, trimming is generally performed prior to flanging, the shapes and sizesof trimming line became a key factor influence flanging forming performance and forming precision,though there are a lot of relevant research results currently, but we haven’t had a way can be easilyused in the production practice to find the trimming line quickly and effectively, so the prediction oftrimming line become a problem must to be solved in mold industry.The theory of one-step inverse method is studied in this paper, and in order to fit the actualsituation of3D flange surface, the original theory is modified, an initial geometrical developmentmethod with element layer is proposed based on one step inverse analysis theory. The flange meshcan be unfold onto the die surface layer by layer according to nodal adjacent element relation, then theabove development mesh is smoothed by mesh smoothing method with sliding constraint surface inorder to delete overlap and distorted mesh, the3D initial mesh can be obtained for one step inverseanalysis method. The precision trimming line of3D complex part can be obtained by plasticityiteration of one step inverse analysis.According to the progressive die parts with technological characteristics，a prediction method oftrimming line based on technological characteristics was put forward. Then the trimming line will getby one-step inverse method after the characteristics separated from flanging area, and get the middleconfiguration of this process, then move the separated technological characteristics to thedevelopment flange mesh, so formed a complete middle configuration.A method of3D trimming line error adjustment is proposed, the form error can be obtained bycalculating the normal distance between the simulate parts boundary nodes and the target partsboundary nodes, then adjusting the boundary nodes on the trimming line according to the form error,Finally, through the calculation of two examples, the comparison of trimming line’s error shows thatthis error correction method can dramatically narrow trimming line’s error.