| 摘要 |
PURPOSE:To improve a dimensional accuracy and to reduce a production cost by performing a piercing with the backward extrusion from the end part of a solid stock with flange, then by forming a through hole by performing a piercing in order through a die and punch. CONSTITUTION:The 1st preform 7 is obtd. by forming the hole 18 reaching to the end face of a flange 5 by performing the backward extruding by the punch 16 fixed to a die 14 and press ram by preparing the solid stock having the flange 5 at the intermediate part. The 2nd preform 7 is then obtd. by forming a hole 28 on the preform 7 with a punch 23 and die 22. In succession, a hole 38 is made by a die 33, die pin 31 and punch 34 and finally a finished product is obtd. by forming the through hole 38 with a die 41 and punch 42. A hollow shaft like part with flange can be manufactured efficiently with a cold forming and the consumable tool cost can be reduced as well. Consequently, the improvement in the dimensional accuracy and reduction in the production cost are enabled in this way.
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