Improved tool design for fine blanking through the application of numerical modeling techniques

The economic and efficient design of tools for metal-forming processes is i ncreasingly being supported by the application of modern techniques such as the finite element method (FEM). This is especially the case for bulk form ing and deep drawing operations. where existing codes have proven to be qui te valuable for the prediction of important process parameters, including p unch force. tool stress distribution as well as the stress and strain distr ibutions within the workpiece itself. In the case of blanking operations, w here a true material separation takes place, standard codes are limited. Ho wever, with recent improvements in FEM codes, it is possible to make a pred iction as to the initiation of cracks and thus part quality. In this paper, the results of investigations of both blanking and fine-blanking processes with the help of FEM are presented. This includes the identification and e limination of critical locations of high tool stress, the determination of tribological conditions such as normal pressure, relative velocity between tool and part and temperature effects, and the prediction of crack initiati on using various rupture criteria. (C) 2001 Elsevier Science B.V. All right s reserved.