| 摘要 |
PURPOSE:To provide a sufficient thickness of wall near a gas inlet and to prevent a decrease in rigidity by burying an insert member having a gas introducing inlet at the center of an area corresponding to the inlet of a mold for a hollow injection molding to be molded by introducing inert gas into melt resin injected in a mold cavity. CONSTITUTION:An insert member 12 is formed of synthetic resin substantially in an annular state and has an introducing port 13 having the same diameter as that of a gas inlet 4 of an upper mold 1a. The member 12 is brought at the port 13 into contact with the inner surface of the mold 1a in such a way that the introducing port 13 is aligned with the gas inlet 4. Then, when a hollow injection molding is conducted via the inlet 4, the port 13, resin encloses an outer periphery of the member 12, the thickness of the wall near the port 4 becomes substantially the same as a general part to obtain sufficient rigidity. |
