Mold for use in plastic injection molding system and venting pin assembly for use therein

摘要

A mold for use in a plastic injection molding system includes a venting pin assembly which can not only vent an article-defining cavity in the mold but can also eject a formed plastic article in an open position of the mold. A porous insert of the assembly permits air from the article-defining cavity to flow there-through while preventing the passage of molten plastic from the article-defining cavity in a closed position of the mold. A venting pin of the assembly in the form of a hollow ejector pin has an elongated aperture formed therethrough to permit the flow of air therethrough. The porous insert is positioned in the aperture at a gas hole formed through an end surface of the ejector pin. The insert and the gas hole are sized so that the insert and the end surface help to form a "Class A" surface on the article formed in the article-defining cavity.