INJECTION MOLDING APPARATUS AND METHOD OF MAKING FOAMED INJECTION MOLDED PRODUCT

摘要

A method and apparatus for injection molding a foamed product. A short shot of formable resin is injected into a cavity (124) defined by respective inner surfaces (134,136) of a plurality of molding plates (120,122) at an amount less than a volume of the cavity (124), the resin comprising a chemical foaming agent. The injected resin is allowed to foam for a predetermined period of time, during which the injected foamable resin foams and expands to substantially fill the cavity (124) and a portion of an outer surface face of the foamable resin contacts the respective inner surfaces (134,136) of the molding plates (120,122). Pressurized gas is injected into the cavity (124) after the predetermined time has elapsed to urge the skinned outer surface of the foamed resin against the inner surfaces (134,136) of the molding plates (120,122).

主权项

1. A method of injection molding a foamed injection molded product, comprising:
injecting a short shot of foamable resin into a cavity defined by respective inner surfaces of a plurality of molding plates at an amount less than a volume of the cavity, the resin comprising a chemical foaming agent; allowing the injected resin to foam for a predetermined period of time, during which the injected foamable resin foams and expands to substantially fill the cavity and a portion of an outer surface of the foamable resin contacts the respective inner surfaces of the molding plates; and injecting pressurized gas into the cavity after the predetermined time has elapsed to urge the outer surface of the foamable resin against the inner surfaces of the molding plates.