| 摘要 |
PURPOSE:To shorten cooling time by a method wherein through holes for molding are formed into a metal mold by two stages, and injection molding is conducted by one through hole while moldings being previously injected and molded are cooled in the other through hole. CONSTITUTION:A melted composition is injected backing an injector pin 2a into a through hole 1a at an upper stage as a molding 7 manufactured by a preceding process in a through hole 1b at lower stage are left as they are cooled by means of a cooling pipe 6b. After completion of injection, a metal mold 1 and a plate 4 at the fixing side are form-opened, an ejector pin 2b at the lower stage is right moved and the moldings 7 being completely cooled are extruded. The metal mold 1 is half turned up and down, and moved so that the through hole 1b being emptied is upward located and the through hole 1a into which the moldings 7 are filled is downward located, and this process is further repeated. A molding cycle is improved because cooling time is shortened. Or the moldings having no bubble, etc. and a smooth surface are obtained because injection time can be prolonged. |
