FORMING METHOD FOR REFORMED CYLINDER WITH FLANGE

摘要

PURPOSE:To improve the shape accuracy of a finished item by performing a deep drawing with compressing the both faces of a blank plate by providing a counter plate, then by performing a burring by pushing in a punch. CONSTITUTION:A press is actuated by plastic a blank plate 9 working a concentric hole 10 on a die by providing the counter plate 6 which opposes to a punch 4 in a liquid pressure chamber 2. The blank plate 9 is pushed into the liquid pressure chamber 2 by being pinched between the punch 4 and plate 6 and a deep drawing is performed as well with the blank plate 9 being strongly pressed from the lower face by the plate 6 by its winding on the shoulder of the punch 4 and the side wall part with the generation of an opposite liquid pressure (q). The flange forming is then performed with the burring of the plate 6 by the punch 4 by releasing the liquid pressure by retreating it to the lower part of the liquid pressure chamber 2. In this way, the shape accuracy of a finished item is improved because the forming with good straightness without the bulging on the side wall part can be performed.