INJECTION MOLDING OF MULTILAYER ARTICLES WITH POST-PULLBACK PRESSURE MONITORING

Abstract: in one aspect, a method of molding a multilayer article comprises causing a surface layer material injection unit to commence injecting a surface layer material into a mold cavity via a surface layer material channel. then, an internal layer material injection unit commences injecting an internal layer material into the mold cavity an internal layer material channel. then, during application of a hold pressure upon the surface layer material in the surface layer material channel and with the surface and internal layer material injection units in fluid communication with one another, a pullback stroke is effected at the internal layer material injection unit. after a delay interval, at least one physical parameter indicative of a post-pullback pressure of the internal layer material is detected, and an indicator of pullback effectiveness is generated based on the post-pullback pressure indicated by the at least one physical parameter relative to a threshold pressure.

Inventor(s): Damish Jaidka, Douglas James Weatherall

CPC Classification: B29C45/77 (SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms ; making laminated products by combining previously unconnected layers which become one product whose layers will remain together - ))

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