| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a different diameter branch pipe which can prevent the large size, and can satisfy a standard size, as well as increases the productivity by reducing the manufacturing cost, and simplifying the manufacturing process. SOLUTION: A branch pipe 1 having plural openings 2A, 2B, and 3A, and making an olefine system resin as the raw material, is obtained by an injection molding, and the opening 3A to be the branch pipe part, of the openings 2A, 2B, and 3A, is heated and softened, the softened opening 3A is inserted in a throttle die in its axial line direction, it is formed by contracting so as to reduce the outer diameter of the opening 3A, and the inner peripheral surface of the opening 3A made in a smaller diameter is cut to form in a prescribed inner diameter. As a result, a desired different diameter branch pipe 1 can be obtained.</p> |
