| 摘要 |
A mold for injection molding of a plastic bottle cap (10) has a cavity (36) which defines the outside slope of the top and skirt of the cap. A core (41) and a core insert (42) fixed to the top of the core define the inside of the cap and constitute a single, non-moving part. A tapered stripper ring (43) below the cavity engages the base of the cap skirt (13). After the cap has been injected through a hot tip (37) in the cavity, the cavity is retracted. The stripper ring is then elevated relative to the core by means of ejector pins (44). As this is proceeding, air is released under the top of the cap to break a vacuum tending to hold the cap on the cap insert. The cap is thus ejected from the mold. A reduced cycle time is achieved. The wall thickness of the cap may be reduced, thus reducing material cost.
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