| 摘要 |
PURPOSE:To make the wall thickness of a molded body thin and prevent the generation of sink marks by providing a hollow section having height and width of specified value or more and formed by force feeding pressurized gas at the time of injection molding. CONSTITUTION:For example, a mat guard for automobiles is provided with a hollow section 1 having its height and width ratio of 3 or more and formed by force feeding pressurized gas at the time of injection molding. The hollow section 1 is formed in the state that only an opening 2 formed by force feeding of pressurized gas at the time of injection molding remains and in the state of not having any other openings. Also, the hollow section 1 is formed at the time of injection molding and the pressurized gas in the hollow section 1 is exhausted and further the slight volume of resin is injected to block the opening 2 and the hollow section 1 can be formed without any openings. As the the opening 2 is small, even when the opening is formed on the site other than the bonding surface 4 of the mat guard, the appearance of mat guard can be retained. Even in the case that the injection molded body is 3 or more of H/W, because of the presence of the hollow section 1, the injection molded body without defective appearance generated by sink marks can be manufactured. |
