Abstract: A nozzle for injection molding is made of at thermally conductive metal material but is thermally conductively blocked or interrupted. An abrupt reduction in wall thickness and/or a gap in the continuity of thermally conductive material occur along the nozzle material passageway. This provides a localized restriction to thermal conduction, causing a reduction in heat flow from the mold to the material supply while cooling the melt material near the end of the nozzle. This material, which is relatively cooled to near the mold temperature, becomes the last injected material when filling of the mold is completed, occupying the area of the sprue. As a result, the sprue is relatively cool, thus reducing stringing and shortening mold cycle time.

Abstract: Mold cycle time is accelerated by employing thermally insulating surface temperature boosters, which are of a minimum thickness to promote cooling by heat transfer through the boosters. According to the thermal transfer properties of the insulating boosters and the respective temperatures of the molten material and the dies, the temperature of the cavity surface is raised by contact with the molten material to equal or exceed the temperature required to produce a molded article, preferably just until the time that the mold is fully filled. Heat transfer through the boosters to the dies then cools and solidifies the molded article until it can be removed from the mold. The temperature boosters result in increased cavity surface temperatures, such that the mold dies can be kept at substantially lower temperatures. The overall result is a reduction in mold cooling time and therefore acceleration of mold cycling.

Abstract: Mold cycle time is accelerated by employing thermally insulating surface temperature boosters, which are of a minimum thickness to promote cooling by heat transfer through the boosters. According to the thermal transfer properties of the insulating boosters and the respective temperatures of the molten material and the dies, the temperature of the cavity surface is raised by contact with the molten material to equal or exceed the temperature required to produce a molded article, preferably just until the time that the mold is fully filled. Heat transfer through the boosters to the dies then cools and solidifies the molded article until it can be removed from the mold. The temperature boosters result in increased cavity surface temperatures, such that the mold dies can be kept at substantially lower temperatures. The overall result is a reduction in mold cooling time and therefore acceleration of mold cycling.