| 摘要 |
PROBLEM TO BE SOLVED: To minimize grinding allowance at the time of grinding a sintered compact obtained by sintering a green compact and to improve the yield of pellet production. SOLUTION: A pellet-shaped green compact 12 is formed by filling a through hole 15a of a die 15 of a forming die 14 with a powder 11 and inserting a lower punch 16 and an upper punch 17 to press the powder. The through hole consists of a straight hole 15b and a tapered hole 15c connected to the upper end of the straight hole and gradually increased in hole diameter toward the upper part. The through hole is filled with the powder in a state where the lower punch is inserted up to a prescribed position of the straight hole, and the upper punch is fixed in a state where it is inserted to a prescribed position in the upper part of the tapered hole. Subsequently, the lower punch is allowed to ascend to the lower end of the tapered hole or to the vicinity of the lower end, by which the powder is pressed to the prescribed density and formed into a green compact. Then, the green compact is pushed out of the through hole by removing the fixing of the upper punch and allowing the lower punch to ascend further.
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