Deep drawing with developed blank of aluminum sheet without blank holder

Using the developed blank, it is possible to form the deep container in one stage. The conventional deep drawing is carried out using punch, die and blank holder. Deformation of divided flange portion of the developed blank seems to be small in the deep drawing. It is possible to carry out the processing without blank holder. When the blank holder is not used, the processing condition in which the forming become very severe. If the case in which the blank shape is not appropriate, gap occurs between flanges or overlap generate on the flange. In this paper, the examination was carried out in detail on flange state of the developed blank. The result was showed that the shape of the flange is no necessity of satisfying the condition of 'the circular arc length is constant', and the forming is possible in the flange of shape of 'parallel linear'. Blank shape that was optimum for carrying out the drawing without blank holder was clarified.