2014 Volume 55 Issue 638 Pages 233-237
Push-back blanking is a two-step burr-free blanking process, in which a sheet metal is half-blanked and then pushed back between platens up to the original sheet thickness. However, when conducting this process in a progressive die system, an additional step is required to eject the blanked part from the sheet scrap. In order to reduce the number of steps, the incorporation of an ejection mechanism into the push-back step is proposed in this study, with this mechanism, a burr-free product could be separated and ejected in the push-back step using the lower platen with a hole. Experiments were carried out on a mild steel sheet, and conditions for successful push-back blanking were investigated. The optimum conditions obtained were applied to the revised push-back step. It was confirmed, through the experiments and FE analysis, that the success of the process depends on the diameter of the hole in the lower platen, and that, under the optimum hole diameter, burr-free parts with the same cut edge quality as those obtained by conventional push-back blanking are obtained with a reduced number of steps.