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3/24/2014 | 1 MINUTE READ

HEATING/COOLING: Novel Heaters for Injection Nozzles, Extrusion Melt Pipes

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Plasma-sprayed coating with insulating cover provides faster, more uniform heating.


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A new heating system from Nordson Xaloy, New Castle, Pa., can replace conventional heater bands with a heater coating that’s said to provide more uniform heating and 25% to 60% greater energy efficiency. The SmartHeat system saw its debut last October at the K 2013 show in Dusseldorf (see Oct. ’13 Keeping Up). Introduced first as an injection barrel coating, it has since been successfully adapted for use on injection nozzles and extrusion melt pipes or adapters.

SmartHeat consists of two layers of plasma-sprayed, metalized ceramic with a nichrome wire wrap sandwiched between the layers, plus a thermal insulation cover. The thin coating (less than 2 mm) with embedded heater wires is sprayed directly onto the machine component for intimate contact and uniform heating. This is said to heat up the component more quickly and uniformly and with less energy than heater bands. The tightly strapped insulation wrap over the ceramic virtually eliminates heat losses, saving air-conditioning costs and reducing the risk of operator injury.

For nozzles (top photo), SmartHeat coating can simplify maintenance and prevent downtime caused by “blowback,” the backward oozing of molten polymer into the spaces between heater bands and the nozzle. Available on new nozzles or as a retrofit, the coating is said to be easily cleaned without stopping production.

Melt pipes or adapters can transfer melt from the extruder to feedblock or die over considerable distances, making it difficult to maintain melt-temperature uniformity. Replacing band heaters with the continuous SmartHeat coating helps ensure uniform temperatures over extended lengths. One of the first users of SmartHeat for this application is Paragon Films, Broken Arrow, Okla. (bottom photo).