| 摘要 |
PURPOSE:To perform satisfactory upsetting by restraining both ends of a blank material by the central punch of upper and lower dies having a specific gap length, extruding successively the blank material by the knock-out resulting from descending of the dies and forming the material into a prescribed shape by the final descending of a press. CONSTITUTION:A blank material 1 is inserted into the central hole of a lower die 16 lifted by a cushion pin 18 and an upper die 5 is moved downward. Both ends of the blank material are held by means of an upper punch 7 and a lower punch 21, and a specific gap (l) is maintained by the contact between a holder 6 and a guide 15 as well as a pin 11. The dies 5, 16 are moved downward according to descending of a slide 3, and the blank material 1 is extruded successively into the gap (l) to have a satisfactory shape by the lifting of the punch 21. The die 16 contacts with an anvil 20 but the die 5 descends further until the gap (l) attains a prescribed width, when the pressing is completed. The product having the satisfactory size and shape without having shear droop is obtd. by the satisfactory intermediate bulging. |
