| 摘要 |
PURPOSE:To reduce production cost, while the gate mark treatment after molding is unnecessary by a method in which the three-plate mold of a pin gate type is used, and the pin gate is formed on the end face of a columnlike rotary plastic magnet. CONSTITUTION:A three-plate mold 1 has two templates 11, 12 forming the parting face 1a of the mold and one runner stripper-plate 13 forming a runner- removing face 1b, and then upon each mold opening, the runner-removing face 1b is opened and the runner is removed. On the template 12, two pin gates 16 injecting raw material into each cavity 111 from the runner 15, are formed in the part of the template 12 forming the end face of a rotary plastic magnet. The pin gate 16 is connected to the cavity 111 at its small point, and the runner may be easily teared off from a molded object by opening the mold, and its gate mark is small. Accordingly, the demagnetization and remagnetization for carrying out gate-cutting treatment and gate mark treatment become unnecessary, and a product is obtained immediately after it has been molded and discharged. |
