Thick-Film Heating
December 2003
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Watlow Electric Manufacturing Company's new line of hot runner nozzle and manifold heaters reportedly allows hot runner manufacturers to assist customers in becoming more efficient and reduce costs. The new technology, says the company, eliminates the disadvantages and unreliability associated with traditional cable and tubular heaters. The company's thick-film technology reportedly enables hot runner manufacturers to uniformly apply precisely calibrated heat with pinpoint accuracy at temperatures up to 500°C (925°F).

According to the company, temperature uniformity is critical in avoiding hot or cold spots in the mold that can cause thermal degradation or flow restrictions. Both can affect final part quality and shot-to-shot consistency. The company says that its new technology offers the injection molding industry a high-performance, low-profile hot runner nozzle heater that can provide a uniform melt temperature for equal cavity filling and improved part quality. The direct surface contact of the thick-film material to the cylindrical stainless steel sleeve reportedly creates optimal heat transfer, while the non-porous glass film prevents moisture absorption, which results in dielectric failure in cable heaters.

The technology also allows the thermocouple to be immersed directly into the hot runner nozzle. According to the company, unlike commonly used coiled cable heaters that have internal thermocouples, the thick-film nozzle heater reportedly allows for the direct measurement of the nozzle temperature, not the heater temperature, resulting in quicker heat up and less thermal jag between the heater and the nozzle.

Watlow Electric Manufacturing Company

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