| 摘要 |
PROBLEM TO BE SOLVED: To obtain a ferrite core having the high accuracy of shape by firing a compact after obtaining the compact whose density is uniformized by uniformly controlling forming pressure which acts on each part of the ferrite core and to stably obtain the ferrite core having the high accuracy of shape by obtaining the compact whose density is uniformized without being affected by the mechanical variation of a press- forming device with the elapse of time and the change in the powder characteristic of the raw material of the ferrite core. SOLUTION: The press-forming device is provided with a pressure gage 12 for detecting pressurization of a middle die and a pressure gage 11 for detecting pressurization of a lower die, the quantities of pressurization per unit area which act on the each part of the lower dies 2, 3 and the middle die 4 are detected and these quantities of pressurization are controlled so as to equalize to the quantity of pressurization per unit area by an upper die 5. Moreover, by performing the control of the quantities of pressurization whenever the ferrite cores are formed, the compact having uniformized density is stably obtained without being affected by the mechanical variation of the press-forming device by the elapse of time and the change in the powder characteristic of the raw material for the ferrite core.
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