Apparatus and method for injection molding articles with sub-surface

Abstract

Method and apparatus are disclosed for injection molding an article having at least one sub-surface portion. The apparatus includes an article mold having at least one cavity with a wedge-receiving aperture and a wedge insertable within the wedge-receiving aperture for receiving the sub-surface portion of the article. The wedge is movable between a wedged position, wherein the wedge is firmly seated within the wedge-receiving aperture and an unwedged position, wherein the wedge is movable with respect to the article mold to free the sub-surface portion of the article when ejecting the article from the cavity. The sub-surface portion of the article can include a part to be held within the cavity during injection molding, or an injection molded portion of the article forming a normally die locked portion of the article. The apparatus can also include a multi-piece mold cavity removably engageable within aligned apertures of a separable mold base. The multi-piece mold cavity includes tapered sidewalls for self aligning engagement with the sidewalls of the apertures in the mold base. The multi-piece mold cavity is assembled into a single unit at an assembly station prior to insertion into one of the mold base apertures at a molding station, and after injection molding, the multi-piece mold cavity is ejected from the mold base prior to disassembly and ejection of the molded article at a disassembly/article ejection station.