| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a workpiece forging method enabling miniaturization of a forging device, and capable of shortening a knockout stroke. <P>SOLUTION: In a try step, a correlation between an upward protrusion length L of rod-like workpiece 23 and a pressing force F is found out. In a mass production step, the pressing force F of an upper die punch 24 is applied to the correlation to determine the length L from an upper surface 51 of a partial die 36 to the upper end 52 of the rod-like workpiece 23. The partial die 36, in which the upward protrusion length L of the rod-like workpiece 23 used for mass production is fitted for the length L from the upper surface 51 of the partial die 36 to the upper end 52 of the rod-like workpiece 23 obtained in the former step, is selected, and forging is carried out by using the selected partial die 36. Even when the workpiece is long, the upper end of the workpiece just exceeds relative to the upper surface of the partial die by a desired height, therefore, a flange part is formed without dropping of a material from a lower die even when the upper die punch is lowered to carry out the forging. <P>COPYRIGHT: (C)2012,JPO&INPIT |
