| 摘要 |
PURPOSE:To make it possible to easily form a nondeformed molded body using a simple and low-priced injection molding metal mold by a method wherein, using the injection molding metal mold provided with a specific strip groove on the circumferential surface of a core member, a ringlike molding body is fixed to the core memory, and after the mold has been released, the molding body is picked out by projecting it from the core member. CONSTITUTION:A strip groove 16 of 0.001-1 mm in depth is provided on the circumferential surface of an injection molding metal mold whereon the cavity of the core 10 will be formed. When a plastic magnetic ringlike molded body is formed, material is injected from the nozzle of an injection molding machine, it is filled up in a ring- shaped cavity 17 and molded in a magnetic field. When the molding is completed, a movable metal mold member is separated from a fixed mold member by moving a movable mold supporting plate, and then an ejector rod 14 is thrusted up, the knockout plate 6 coupled with the ejector bars 15 and 16 is pushed up and the ringlike molded body left around a core 8 is picked out from the core 10. As a result, the molded body can be formed easily using an uncomplicated structure and low-priced mold without deformation.
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