| 摘要 |
PURPOSE:To prevent creases generated on the edge of a cup and to prevent tensile stress generated on the side wall of the cup from becoming large more than necessary by pressing and forming the end face of the material cup by end face of stepped part of a stepped punch. CONSTITUTION:The tip 8a of a punch 8 is fitted to the cup part of a cylindrical material 1, and a face 8b is brought into contact with the end face 1b of the cup. This cylindrical material 1 is placed on a die 3 through a guide ring 9. Under this state, load W that thrusts the punch downward is applied by a press device and ironing is performed pressing the end face 1b of the cup always by a face 8b of the punch 8b. As the end face of the cup of the cylindrical material 1 is pressed always by the face 8b of the punch 8, the waving of the end face of the cup 1b caused by deformed shape, uneven reduction rate of the thickness, uneven elongation of inner diameter and outer diameter of the cup etc. can be prevented. |
