FE modelling of multi-stage drawing of a miniature tubular component with a middle flange and rounded edge

An FE model to simulate a multi stage deep drawing/redrawing process of a miniature tube with a flange mid-way its length was developed. At the final stage of the manufacturing sequence the upper trimmed end of the tube was curled. The curling operation progressed to a point until the curling force caused the collapse of the flange. The objective of the research was to define the limiting geometric and process parameters for the curling operation. Two alternative FE models, 3D and 2D axisymmetric, were adopted. The 3D model was used to investigate anisotropic behaviour of the material during the first drawing operation in order to establish whether there were conditions that warranted resorting to 3D modelling. Eventually the 2D axisymmetric model was used to simulate the material flow in all 11 forming operations. Additionally a springback analysis was performed after each operation; strain and stress states resulting from the unloading of the formed component were used as the initial states for the succeeding operations. The FE simulation results matched the experimental results and led to the conclusion that the accuracy of trimming played a critical role in the outcome of the curling operation.