| 摘要 |
PURPOSE:To obtain a molding body with uniform density, by splitting a punch molding a stepped part of the molding body into a part corresponding to stepped bottom and a part corresponding to stepped projection and varying the position of the split punches. CONSTITUTION:Granulated powder 3 of Mn-Zn ferrite having a specific grain distribution is filled in a space of a die 2 and pressed with a top punch 1 from upward and with a bottom punch 4 from downward. The punch 4 is formed with the 1st bottom punch 5 to form a stepped bottom and the 2nd bottom punch 6 to for a stepped projection. Both of them are individually operated and the punch 6 is fixed to the die 2. At the press molding of the granulated powder 3, the punch 6 drops when the punch 1 drops, and in this case, when the falling of the punch 5 is delayed for <=1.0sec from the operation of the punch 1 after the start of pressing, the difference of density between a stepped bottom 8 and a stepped projection of a molding body 7 can be prevented. |
