| 摘要 |
PURPOSE:To form uniform resin layer on the whole by using single kind of resin material and making heating condition nearly uniform, even when thick walled part and thin walled part are formed by a method wherein the resin material is placed on the thick walled part of the cavity of a mold and heated and gas is blown in the resin material under flowable state. CONSTITUTION:Resin material 25 is placed on the thick wall forming part 14 of the cavity 13 of a forming mold 10 and, after mold closing, heated by high-frequency dielectric heating. The resin material 25 starts to expand in volume and, at the same time, softens and turns into flowable state. By feeding compressed gas consisting of inert gas such as nitrogen gas or the like through a gas blow pipe 24 so as to locally cool the part, which comes into contact with a supporting member 23, of the resin material 25 so as to harden to some extent quicker than the remaining part in order to introduce gas in the resin material 25 by breaking through the resin, which comes into contact with the supporting member 23. Hollow part 26 is produced in the resin material 25 and gradually enlarged by further feeding gas continuously, resulting in flowing the resin material 25 so as to spread it in the cavity 13 in order to stick it onto a molding surface. By cooling and hardening the resin material 25 as the pressure of gas is held, a hollow resin molded item 1 is obtained. |
