A molding method for a synthetic resin molding that includes a molding body, a bent portion, and a flange. The bent portion and the flange are continuous in a longitudinal direction of the side edge. The flange includes a wide portion and a narrow portion. The molding method for the synthetic resin molding includes arranging a gate at a position corresponding to an end of one side of the flange in a longitudinal direction, setting a relationship S1≦S2, where S1 is a cross-sectional area of the wide portion of the flange, and S2 is a cross-sectional area of the narrow portion of the flange adjacent to and downstream from the wide portion in a flow of molten resin, and performing injection molding using a colored resin material containing a luster agent kneaded in the material.

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.

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.

A molding method for a synthetic resin molding that includes a molding body, a bent portion, and a flange. The bent portion and the flange are continuous in a longitudinal direction of the side edge. The flange includes a wide portion and a narrow portion. The molding method for the synthetic resin molding includes arranging a gate at a position corresponding to an end of one side of the flange in a longitudinal direction, setting a relationship S1S2, where S1 is a cross-sectional area of the wide portion of the flange, and S2 is a cross-sectional area of the narrow portion of the flange adjacent to and downstream from the wide portion in a flow of molten resin, and performing injection molding using a colored resin material containing a luster agent kneaded in the material.

An injection molding apparatus comprising an injection molding machine, a manifold, a closure valve pin, a first actuator having a linear or axial driver, a second actuator comprising a rotor interconnected to either the closure valve pin or to a second valve pin such that either the closure valve pin or the second valve pin is rotatably driven in unison with the rotor around the rotation axis, the closure pin or second pin being disposed and rotatable within the flow of injection fluid flowing through a flow channel leading to a mold cavity.

An injection molding apparatus comprising an injection molding machine, a manifold, a closure valve pin, a first actuator having a linear or axial driver, a second actuator comprising a rotor interconnected to either the closure valve pin or to a second valve pin such that either the closure valve pin or the second valve pin is rotatably driven in unison with the rotor around the rotation axis, the closure pin or second pin being disposed and rotatable within the flow of injection fluid flowing through a flow channel leading to a mold cavity.