Abstract: The present invention provides an electrically heated nozzle for injection molding which is insulated to prevent conduction of electricity and loss of thermal transmission to the casing, wherein at least a part of the electrical insulation comprises a layer of dielectric insulator material with an electrical resistance wire wound spirally thereabout and another dielectric insulator layer thereover. Also disclosed is a method for making such a nozzle which includes the steps of applying a first insulator layer, winding electrical resistance wire about the first insulator layer, applying a second insulator layer, and applying a casing layer thereover. The first and second insulating layers may be provided by spraying or through telescoping, self-supporting sleeves.

Abstract: The present invention provides an electrically heated nozzle for injection molding which is insulated to prevent conduction of electricity and loss of thermal transmission to the casing, wherein at least a part of the electrical insulation comprises a layer of dielectric insulator material with an electrical resistance wire wound spirally thereabout and another dielectric insulator layer thereover. Also disclosed is a method for making such a nozzle which includes the steps of applying a first insulator layer, winding electrical resistance wire about the first insulator layer, applying a second insulator layer, and applying a casing layer thereover. The first and second insulating layers may be provided by spraying or through telescoping, self-supporting sleeves.

Abstract: The invention relates to an injection molding apparatus including a mold block, a nozzle, a gating system and a slug heater. The mold block defines a mold cavity having a mold cavity inlet. The nozzle has a nozzle inlet. The nozzle inlet is fluidically connectable downstream from a melt source. The nozzle inlet is upstream from the mold cavity inlet. A melt flow passage extends from the nozzle inlet to the mold cavity inlet. The gating system includes a valve pin and an actuator. The valve pin is movable between an open position wherein melt flow is permitted into the mold cavity, and a closed position wherein the valve pin blocks the melt flow passage to prevent melt flow into the mold cavity. The actuator is operatively connected to the valve pin to move the valve pin between the open and closed positions.

Abstract: An injection molding hot runner nozzle includes a nozzle body comprising a nozzle core, a nozzle tip, and a melt passage extending through the nozzle body for conveying melt from a manifold through the nozzle tip and to a gate of a mold cavity. A cylindrical sleeve is disposed around the nozzle body, the sleeve being slidably removable from the nozzle body. A wire heating element for heating melt in the melt passage is is spirally wound about the sleeve. A temperature sensor comprising a wire is spirally wound about the sleeve.

Abstract: An injection molding nozzle with a collar having two segments mounted around the rear end of an elongated central body having a hollow central core. A helical portion of an electrical heating element is cast in a copper alloy conductive portion around the central core. The heating element has a pair of lead portions which extend outwardly through the collar into a ceramic insulative connector. The lead portions extend in stainless steel protective tubes having inner ends rigidly cast in the copper alloy conductive portion over which the insulative connector is mounted.