| 摘要 |
PROBLEM TO BE SOLVED: To provide a port hole die of excellent economy for consistently manufacturing a hollow extrusion die material of excellent dimensional accuracy without any uneven thickness, and reducing wastes of materials. SOLUTION: A male die 2 comprises a ring part 4, a bridge part 5 provided along the inner radial direction of the ring part 4, and one or a plurality of forming projecting parts 6, 7 provided on a front end part in the extruding direction of the bridge part 5 to form a hollow part 31 of a hollow extrusion die material 30. The ring part 4, the bridge part 5, and at least the forming projecting parts 6 and 7 are integrated with each other. A female fitting recessed part 4c is formed on the front end face in the extruding direction of the ring part 4 along the extruding direction, and a plate-like female die 3 having a forming hole 13 to form an outer circumferential part 32 of a hollow extrusion die material 30 is tightly fitted to the female fitting recessed part 4c. In this condition, the front end faces in the extruding direction of the male die 2 and the female die 3 are formed flush. COPYRIGHT: (C)2004,JPO
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