| 摘要 |
PROBLEM TO BE SOLVED: To provide a powder compaction process of compacting raw material powder and obtaining a powder compact by which even in a pipe-shaped powder compact with uniform inside diameter and outside diameter or a powder compact with a shape in which the outer circumferential face is parallel to the axial direction such as a spur gear shape, the occurrence of a neutral layer can be effectively prevented, and a powder compact with a uniform density over the whole region is obtained as a result. SOLUTION: A helical groove 21 is formed over the whole region of the outer circumferential face of the intermediate part of a core rod 24. Further, a helical tooth 17 is formed at the whole face of the inner circumference of a lower punch 14. The helical groove 21 is always engaged with the helical tooth 17 in a threadedly engaged state. When raw material powder 1 packed into a cavity 28 is compaction-molded by an upper punch 29 and the lower punch 14, the core rod 24 lowers simultaneously with the lowering of the upper punch 29. In this way, by the threaded engagement between the helical tooth 17 and the helical groove 21, the core rod 24 rotates with the axial center 24c of the core rod 24 as a rotary axis, and the raw material powder 1 is compaction-molded. COPYRIGHT: (C)2009,JPO&INPIT |
