| 摘要 |
PROBLEM TO BE SOLVED: To develop a compacting method for a green compact in which density differential is small in each part and which has no horizontal neutral layer since a sintered valve guide having a long cylinder shape and the tapered outer periphery lower end part in which each part of the green compact easily becomes heterogeneous. SOLUTION: In a process in which a powder in a die cavity formed by a die 1, lower punch 2 and core rod 4 is compressed and formed between the upper punch 3 and the lower punch 2, the core rod is fixed to the upper end of the lower punch, the core rod is relatively hoisted and lowered with respect to the die, and a position of a low density part generated on the die side is allowed to be different from a position of a low density part generated on the core rod side.
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