Abstract: A heater is provided that includes a resistive layer formed by a layered process (e.g., thick film, thin film, thermal spray, and sol-gel) and two electrical lead wires connected to the resistive layer. The resistive layer has sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a sensor, and the resistive layer is in communication with a two-wire controller through the two electrical lead wires. Preferably, the sensor is a temperature sensor, and the heater includes additional layers formed by layered processes.

Abstract: An instrumented heater sleeve is provided that has a plurality of zones, a dielectric layer disposed over an outer surface of the sleeve, a resistive element layer disposed over the first dielectric layer, and a plurality of pairs of lead wires secured to a portion of the resistive element layer. Each pair of lead wires is connected to and corresponds with each of the zones and a protective layer is disposed over the dielectric layer. An amount of power is supplied to each of the zones and adjusted during a test run, or multiple test runs, to achieve a desired temperature profile along a heating target such as a hot runner nozzle. Methods of designing a hot runner nozzle heater using the instrumented heater sleeve are also provided.

Abstract: A hot runner nozzle heater system is provided with a layered heater in communication with a two-wire controller, wherein a resistive layer of the layered heater is both a heater element and a temperature sensor. The two-wire controller thus determines temperature of the layered heater using the resistance of the resistive layer and controls heater temperature through a power source.

Abstract: A hot runner nozzle heater is provided that includes a sleeve defining a slot extending along a length of the sleeve. A first dielectric layer is disposed over an outer surface of the sleeve, and a resistive element layer is disposed over the first dielectric layer, wherein the resistive element layer defines a resistive circuit pattern that is preferably formed by a laser trimming process. A pair of terminal leads are secured to a portion of the resistive element layer thus defining a termination area, and the termination area is positioned proximate the slot and away from the proximal end and the distal end of the sleeve. A second dielectric layer is disposed over the resistive element layer but not over the termination area, a third dielectric layer is disposed over the termination area, and a protective layer disposed over the second dielectric layer and the third dielectric layer.

Abstract: A heater system is provided with a layered heater in communication with a two-wire controller, wherein a resistive layer of the layered heater is both a heater element and a temperature sensor. The two-wire controller thus determines temperature of the layered heater using the resistance of the resistive layer and controls heater temperature through a power source. Furthermore, a heater system using a layered heater in communication with a two-wire controller for a specific application of a hot runner nozzle in an injection molding system is provided by the present invention.