| 摘要 |
PURPOSE:To improve the dimensional accuracy of a molded article by a method wherein injection molding is performed with low mold clamping force under the condition that injection pressure conveying channel material, which turns into lowly viscous fluid at injection temperature, is included as conveying channel in the molded article. CONSTITUTION:In an article 2 to be injection-molded through a gate 1, injection pressure conveying channel material 3, which extends from the gate 1 to the neighborhood of the ends 4 of the article 2, is provided as the inner core included in synthetic resin. The conveying channel material 3 is formed in the thicker wall part of the molded article 2. An auxiliary injection cylinder 21 is arranged on the side of the main injection cylinder 20 of an injection molder so as to firstly inject normal resin by the amount insufficient for filling a mold cavity through the gate 1 with the main injection 20 and secondly inject lowly viscous resin fluid through the gate 1 with the auxiliary injection cylinder 21 in order to run to the thicker wall part of the molded article 2. By continuing the forcible feeding of the lowly viscous fluid, the mold cavity is filled so as to favorably mold the molded article. Accordingly, injection molding can be carried out with low mold clamping force and the accuracy of the molded article can be improved. |
