Hole flanging and punching of circular plates with conically headed cylindrical punches

Abstract

To investigate the mechanics of the hole-flanging process, the quasi-static drifting and punching of thin circular plates with conically headed cylindrical punches was carried out for different materials. The deformation modes of the defected plates and the loads associated with them at different stages of punch penetration were obtained and the results are analysed by use of an elementary theory. The neck characteristics in the flange formation, which are of basic types—lip, petal and plug—were found to be dependent on punch semi-angle, material, and size of the initial hole in the plate. The change-over from lip to petal mode and the stage at which fracture occurs were studied. A simple analysis that predicts some features of neck formation, the onset of plugging and features of fracture development is also given and results obtained by its use are compared with experimental results.