| 摘要 |
A system and apparatus for injection molding articles of crystallizable polymeric materials in a substantially completely amorphous state is provided. The system includes (i) a mold defining an article formation cavity and an outer cavity connected by a gate, (ii) a melt transport mechanism including a bushing having a distal portion located in the outer cavity in close proximity to the gate inlet, and (iii) a source of molten material. The geometric configurations of the distal portion of the bushing, the inner portion of the outer cavity and the gate, and the relative locations of the distal end of the bushing and the inlet of the gate are each selected such that melt material may flow from the source through the melt transport mechanism and gate into the article formation cavity. The melt transport mechanism is maintained at a temperature above the characteristic crystal melt temperature of the polymeric material. The mold temperature is maintained well below the minimum characteristic glass transition temperature of the polymeric material. Further, the geometric configuration of the elements is selected such that the vestige which protrudes from the completed article has a minimum length, and such that during the interval between successive cycles only a small volume of melt located between the discharge orifice of the bushing and the outlet of the gate is allowed to crystallize.
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