| 摘要 |
PURPOSE:To prevent the generation of a recessed fold in a work by providing air ways extending to the outside of the work on the outside surface of an elastic body to be fitted into the work, and communicating the spacing between the elastic body and the work, via the air ways, with the outside, when the elastic body shrinks. CONSTITUTION:Circular cylindrical urethane rubber 29 projecting donwnward from a punch 19 is mounted to said punch. Plural grooves 21, which are spaced from each other circumferentially, are provided on the outside peripheral surface of the rubber 20, at about 0.2-0.4mm. depth. A work W is fitted into the recess 11 of a die 10, and the punch 19 is lowered to expand forcibly the work W by the rubber 20 in such a way that the work contacts tightly with the inside surface of the recess 11, thereby forming the work W to the shape conforming to the inside surface of the recess 11. The punch 19 is then moved upward to remove upward the rubber 20 from the work. When the rubber 20 shrinks in such operation, the spacing 22 between the rubber 20 and the work W is communicated with the atmosphere in the part upper than the work W, via the grooves 21, and therefore no negative pressure is generated in the spacing 22, and the work W is prevented from recessing to the spacing 22 side. The work W is therefore prevented from folding. |
