Abstract: A die apparatus capable of removing powder adhering to cut surfaces so as to securely form a cavity in a desired shape includes divided dies reciprocatingly driven by sliders to comes into contact with one another so as to form a cavity. Punches are inserted into the cavity from above and below the cavity. Each divided die is provided with cut surfaces that come into contact with the other divided dies. A gas passage connected to a gas injection port that injects gas from the cut surface is formed in each divided die.

Abstract: Provided is a mold device which forms a cavity of a predetermined shape, even if timing of reaching a predetermined position for forming the cavity is different among dies, due to a difference in advancing speed among the dies. A die segment 3a butts against a pair of die segments 3b and 3c at a first parting surface 4 and a second parting surface 5, respectively. In the first parting surface 4, a longitudinally protruding part 6 which is locally protruding is formed, and thereby a first guide surface 9 which extends parallel to a travel direction of the die segment 3b is formed. In the second parting surface 5 of the die segment 3b, a longitudinally recessed part 7 which is locally recessed is formed, and thereby a second guide surface 10 which butts against the first guide surface 9 of the die segment 3a is formed.

Abstract: Material powder 17 is filled in a cavity 16 which is composed of a die 12 having a die hole 11 in a shape matching the contour of a green compact and a lower punch 13. The material powder 17 is temporarily compressed by an upper punch 14 and the lower punch 13 to obtain a preform 18. A punch-out pin 15a is inserted into the preform 18 to punch out a shape of a through-hole 3. The preform 18 is pressurized and compressed by both of the upper and lower punches 14, 13 to obtain a green compact 19. The punch-out pin 15a is pulled out from the green compact 19 and the green compact 19 is taken out from the cavity 16. Further, the green compact 19 is sintered and a pair of leg parts 24 connected continuously at a base part 23 and an undercut part 25 between the leg parts 24 are formed by cutting off a part of a peripheral wall 26 of a through-hole 25a.