| 摘要 |
PURPOSE:To form a cylindrical case by extrusion by a simple process and in high yield, by providing a taper part which prevents a surge generating at the mouth of a cylindrical case to a punch for forming, in forming a cylindrical case of extensible metal from a metallic billet by a backward extrusion method. CONSTITUTION:A pellet 4 of blank material is put on a hole C, having a taper part F of a die 9 of a cylindrical-case extrusion-forming machine consisting of a punch 8 and a die 9 for forming, a knockout pin 10 for ejecting a product and a stripper 11. The die 9 is lowered to press form a cylindrical case 12. In this case, a mouth of the case 12 is pressed down by a taper part D provided to the punch 8, and the circumference of the mouth of case 12 is made to have a fixed height. When the forming is finished, the punch 8 is moved upward, and matters sticking to the punch 8 are brushed off by the stripper 11 after the knockout pin 10 rises to the upper dead point, thus the cylindrical case 12 is obtained as a product. |
