‘Thin-Film’ Technique Boosts Part Finish, Cuts Energy Costs

German researchers want to commercialize a mold coating technology that they feel will improve surface finish of plastic parts and also reduce energy consumption.

It’s a pretty simple idea really. Highly conductive material such as a copper alloy is embedded in a 10-micrometer ceramic layer that also contains a metallurgical thermocouple. The thin layer deposited on a mold cavity and heated to molding temperature instead of the entire tool.

The ceramic layer is produced using a vacuum-based coating technique called sputtering. Alexander Fromm of the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, says the purpose of the ceramic layer is to insulate the heating layer from the tool steel to avoid short circuits and to embed a sensor that can measure the temperature of the tool wall and regulate the process. Thermocouples are made from nickel or nickel-chrome alloy and are each just a few hundred nanometers thick.

Fromm and his colleagues worked with the Kunststoff-Zentrum in Leipzig to perfect the process, which they say is up to 90 percent more energy efficient than other techniques.

The researchers are now looking for industry partners to help prepare the process for use in series manufacture.

Red represents the conductive heating layer; green, the thermocouple; and yellow, the sputtered ceramic.  The thin film is represented as gold on the mold cavities. Credit: Fraunhofer.

Red represents the conductive heating layer; blue, the thermocouple; and yellow, the sputtered ceramic. The thin film is represented as gold on the mold cavities. Credit: Fraunhofer.

About Doug Smock

Former Chief Editor at Plastics World and Senior Technical Editor Design News

Cooling/Heating, Molds & Moldmaking ,

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