| 摘要 |
An improved mold for injection molding suction cups is disclosed. Conventionally, plastic is injected through a runner into a mold cavity defined by at least two mold sections having mating faces which can be moved apart to open the mold cavity and the cavity is shaped to define a suction cup having a head and a cup shaped body which body has an outer circumferential edge between its top surface and its bottom surface. The improved mold creates a wedge-shaped tab during molding of the suction cup. The thin part of the tab is adjacent to the outer circumference of the suction cup, One fills the mold cavity by injecting plastic through a gate which is adjacent to the thick part of the tab, said gate having an opening not larger than one half the thickness of the tab, said opening positioned so as not to intersect a face of the mold section. As the molten plastic is injected, turbulence is kept in the wedge-shaped tab area from which it flows more smoothly into the cup itself, keeping the concave inner surface smooth when the cup is cooled. The suction cup is ejected from the mold cavity in a manner to cause the tab to break cleanly from plastic in the gate, without putting stress or causing distortion to the soft plastic in the cooling cup.
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