PURPOSE: To take out a disk without rubbing strongly the disk by interposing a rubbery elastic body between the disk and a pressure means, bringing it diameter reduction within an elastic limit, and thereafter, bringing it coining, releasing its diameter reduction state after coining, and thereafter, taking out a material disk.
CONSTITUTION: An aluminum blank material 13 having a hole in the center is placed on the lower die 11, the upper surface plate 23 is allowed to descent, a diameter reduction ring 16 is depressed through an elastic ring 20 by a pressure ring 19, and also, a diameter expansion rod 17 is depressed through an elastic rod 21. A die ring 14 is brought to diameter reduction forcibly. In this regard, the diameter reduction and diameter expansion are executed within a range of an elastic deformation. When the upper die is further allowed to descent and coining is executed, as for the blank material 13, its outside diameter expands by a decrease portion of plate thickness, the inside diameter is reduced until it comes into contact with the outside peripheral surface of a mandrel 15 and the smooth surfaces of the upper and the lower dies 11, 12. In such a way, a precise metallic disk being free from shear droop, spring-back and fouling can be manufactured.
SAITO AKIRA
HATA TOMOKATSU
INABAYASHI YOSHITO
YOSHIDA AKISHIGE
KAWASAKI STEEL CO
ITOH C & CO LTD