| 摘要 |
PURPOSE:To manufacture a molding die for plastic discs having a high mass production efficiency by disposing at least two or more cavities of direct gate structure coaxially in line with the inflow direction of molten plastic resin into a mold and providing a restricted pin movable on said axis. CONSTITUTION:Molten plastic resin 41 injected out of an injection nozzle 21 passes through a first sprue 1, and reaches a head 10a of a restricted pin 10, being divided into two by fluid resistance of the head 10a, one of which flows into a first cavity 2, cooled and solidified after being filled in. On the other hand, the other passes through a second sprue 1', flows into a second cavity 2', and after being filled in, is cooled and solidified. The restricted pin 10 is fixed at the most suitable position with a sliding mechanism 15 consisting of a cylinder 12 and a piston 11 and also with a control device 16 outside the mold. As the mold opening action goes on, parting faces between a first template 6 and a second template 6' and between the second template 6' and a third template 6'' are opened, and the molded plastic discs 42, 42' are removed. |
