B29C2045/577

INJECTION MOLDING APPARATUS AND METHOD TO REDUCE BIREFRINGENCE
20190358875 · 2019-11-28 ·

A molding apparatus and method operation for making a molded part are provided. The molding apparatus includes a mold core extending between a generally flat lower surface and an upper surface defining a runner, a fan gate, and a part cavity for forming the molded part. The mold core includes an inner surface defining a plunger cavity extending into the mold core from the upper surface and having a uniform cross-section parallel to the upper surface and open to the gate. A plunger is slidably disposed within the plunger cavity for pulling material from the gate into the plunger cavity. A first pin extends through a first bore in the mold core to move the plunger within the plunger cavity. A hydraulic cylinder interacts with an ejector plate to move the first pin. A second pin also extends through the mold core and is movable perpendicular to the upper surface.