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US 4,390,486 AGranted
Method and apparatus for heating a mold cavity uniformly
AssigneeEx-Cell-O Corporation
InventorsJames W. Hendry, Je-Chin Han
Life of this patent
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AssigneeEx-Cell-O Corporation
InventorsJames W. Hendry, Je-Chin Han
Estimating the term…
This apparatus is used to improve the heat distribution on the cavity surface in foam molding dies where a smooth finish on the resin filled foam molded plastic product manufactured by an injection molding process is desired. This invention improves the method for heating the mold cavity using a condensing vapor in a molding die by a channel and slit type orifice means in the mold around a portion of the periphery of the part to be molded. Another channel and slit type orifice means around the remaining periphery is included in the die for removing the condensing vapor or condensate from the mold cavity. During the heating process when condensing vapor is introduced into the mold the sprue opening to the extruder is sealed by a valve means to prevent condensate from collecting therein.
A process for injection foam molding a thermoplastic plastic resin composition in an injection molding means comprising the steps of:
An apparatus for molding a thermoplastic resin comprising an injection molding means having two mold halves and a cavity means therein, a sprue means in communication with said cavity means through a passage means interposed therebetween, a means selectively operated to seal the passage means between said sprue means and said cavity means and selectively close off the sprue means from the cavity means when condensable vapor is introduced, an inlet means selectively operated to allow condensable vapor into said cavity means and an outlet means selectively operated to allow condensate to be discharged from said cavity, and a seal means peripherally located between said mold halves.
Dependencies are inferred from the claim text.