平押し法における材料への拘束が分離成功条件域ならびに切口面に及ぼす影響

抄録

The cut surface obtained by blanking has burrs, whose occurrence should be prevented. Push-back blanking is one of the burr free blanking methods. This method was consists of two stages. The first stage is a half-blanking stage, and in the second stage the product is separated from the scrap by pushing the half-blanked material. It is known that the range of successful blanking conditions decreases with decreasing scrap width. In this paper, the effects of constraint of the sheet material on the range of successful blanking conditions and the cut surface are discussed on the basis of the results of an experiment when the scrap width is small. The experiment was carried out using a disk-shaped specimen whose outer peripheral surface was constrained in the first stage. This study clarified the following. The constraint of the specimen in the first stage was effective for increasing the range of successful blanking conditions when the scrap width was small. It is considered that the increase in the range of successful blanking conditions is caused by the decreased the bending deformation and the compressive deformation of the scrap in the second stage from the observation of a cross section of the specimen. The shear droop formed in the half-blanking stage and separating stage was decreased when the specimen was constrained in the first stage.