| 摘要 |
PROBLEM TO BE SOLVED: To simply and promptly form the recessed stripes of the inner peripheral surface of a peripheral surface molding mold with a working manday reduced and to reduce the cost of the mold. SOLUTION: When the peripheral surface molding mold which is cylindrical as a whole, has the recessed stripes extending in the central axis direction in the inner surface, and contributes to the section of a molding cavity is produced, a mandrel 2 with protruding stripes 3 extending in the axial direction formed is arranged inside a die 1 on the peripheral surface. A pipe material is passed between the die 1 and the mandrel 2, and the peripheral surface profile shape of the mandrel 2 is transferred onto the inner surface of the pipe material. COPYRIGHT: (C)2004,JPO&NCIPI |
