On the earing in cup-drawing with non-uniform die clearance: analytical, numerical and experimental approaches

Abstract

To minimize the earing incurred by the planar anisotropic properties of sheets, a non-uniform die clearance model was proposed for the cup drawing process. The theoretical earing profile height model with non-uniform die clearance was developed based on the combination of radial strain and thickness strain. The Hill 1948 yield criteria was applied to predict geometric earing profile and the anisotropic parameters were calibrated by optimization. It is observed that the predictions of the theoretical model are in agreement with the results of the cup drawing experiments, and the earing profile height is increasingly decreased by the non-uniform die clearance model. Further to this, a numerical model of the deep drawing process was also carried out using the commercial finite element software Abaqus. The results show that the cup drawing with non-uniform die clearance can not only minimize the earing profile height but also reduce the opening springback and twist springback in the split-ring process.

Keywords

• earing
• non-uniform die clearance
• cup drawing process
• earing profile height
• springback