| 摘要 |
An injection molded metal mold is provided to eliminate defects such as appearance defects of molded products, functional defects of products, or the like, caused by formation of a concave portion in a surface opposite to a gate as a metal mold is used over a long period of time. An injection molding metal mold 1 in which when a melted resin is injected first from a gate into an injection cavity, the rate of resin at the gate is not less than 5 m/sec, and the distance between the gate 5 and a portion opposite to the gate is 0.2 mm to 2.0 mm. In the mold, an exchangeable gate-opposition metal mold member, in the form of an ejection pin, is buried in the portion opposite to the gate. Further an injection molding method using this metal mold is provided. The forward end of an ejection pin bites into a plastic molded product so that the molded product is held ejected when the metal mold is opened. The molded product is ejected by the ejection pin provided oppositely to the injection gate and projecting into an injection cavity after molten resin is injected into the injection cavity.
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