Techniques to mold parts with injection-formed aperture in gate area

Abstract

Methods and systems for co-extruding multiple polymeric material flow streams into a mold cavity to produce a molded plastic article having an injection-formed aperture in gate region of the article are disclosed herein. A method includes providing a valve pin having a distal portion with a first diameter and a mid-portion with a second diameter smaller than the first diameter and providing a mold defining a cavity corresponding to a shape of a resulting molded plastic article. The mold has a recess aligned with a gate region of the mold, extending into the mold and configured to receive the distal portion of the valve pin when the distal portion of the valve pin extends beyond the gate region. The method includes advancing the distal portion of the valve pin into the recess until the mid-portion of the valve pin at least partially extends into the gate region, thereby establishing a flow path for a combined polymeric stream into the cavity at the gate region for forming a molded plastic article having at least one layer of a first polymeric material and at least one layer of a second polymeric material. The method also includes withdrawing the mid-portion of the valve pin from the gate region, thereby forming an injection-molded aperture in the resulting molded plastic article at the gate region.