| 摘要 |
PURPOSE:To achieve a central hole-punching finishing work for a disc molded object simply and satisfactorily without moving a sprue bush by a method in which the tip of the sprue bush corresponding to the central hole of the disc molded object is recessed lower than the surface of the parting line of the sprue bush, and the gate to the cavity for molding the disc is formed of the inner diametrical edge of the sleeve bush and the outer diametrical edge of a punch. CONSTITUTION:The tip 15a of the sprue bush corresponding to the central hole 101 of the disc molded object 100 facing the cavity 3 for molding a disc, is recessed lower than the surface P-P of the parting line of a sleeve bush 14, and the gate 33 to the cavity 3 for molding the disc, is formed with the inner diametrical edge 14a of the sleeve bush and the outer diametrical edge 31a of a punch 30. In the molding of the disc molded object 100 by the mold for molding the disc, the injection nozzle of a molding machine body is advanced in the state of mold closing, and then by pushing said injection nozzle to the nozzle touching surface of the sprue bush 15, molten resin is injected into the cavity 3 for molding the disc through the sprue bush 15 and the gate 33, and said cavity is filled. |
