| 摘要 |
PURPOSE: A blow molding method and apparatus are provided to circulate cooling air in the hollow portion of a plastic molded article molded inside a blow mold, thereby shortening cooling time, and sufficiently cooling the article in order to minimize the defection rate of products, and reduce heat consumption. CONSTITUTION: A blow molding method is as follows: Adhesive portions on two plastic plates heated and softened are pressurized and adhered. The tip of sleeve blow pin is inserted between the plastic plates stacked. A heated air is injected between the plastic plates through the duct of the blow pin in order to hot-mold the plastic plates inside a mold, and then a plastic molded article is hardened after cooling. A first blow pin(30) and a second blow pin(40) are installed at both sides of the hollow portion(75) of the plastic molded article. A first circulation flow path(35) and a second circulation flow path, which form the hollow portion(75) into a circulation path, are respectively installed at the outer peripheries of the first blow pin and the second blow pin. In a molding cycle, the heated and compressed air is supplied to the ducts(31,41) of the first blow pin and the second blow pin in order to mold the plastic molded article inside the mold. In a cooling cycle, the molding ports(39,49) of the ducts are closed, and at the same time a cooling path formed by connecting the first circulation flow path, the hollow portion, and the second flow path is opened, and then cooling air is circulated through the cooling path in order to cool and harden the plastic molded article.
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