Cold runner molds usually consist of two or three plates that has a network of runners that lead to the mold cavities. In this system, the runners act as a delivery system that distributes the molten plastic to the individual molding cavities. That subsequently cools along with the molded part.

In a two plate mold, the sprue and the runner system remain on the ejector side of the tool and are ejected along with the molded part.

In a three plate mold, the sprue and runner system remain opposite of the ejector side of the tool. The three plate mold system automatically separates the runner from the part as the mold opens. In both the two plate and three plate mold systems, the runner.

Hot runner molds consist of mold plates that are electrically heated that contain a network of runners that lead to the mold cavities. In this system, the runners act as a delivery system that distributes the molten plastic to the individual molding cavities. Different than the cold runner system. These runners stay hot when the molded part cools.

In a Insulated runner mold, the heated sprue feeds a huge diameter runner, two inches in diameter or more. This runner is not heated. The mass of plastic prevents the runner from cooling off. This runner feeds gates that has probes that fill the molding cavities.

In a hot runner manifold mold, the heated sprue feeds an heated runner system that feeds gates that have heated probes that fill the molding cavities.