Heraeus Infra-Red Is the Right Choice For Quality Powder Coating of Electric Motor Housings

Phil Black - PII Editor 27/09/2013

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Infra-red radiation is readily absorbed by powder, promoting faster gelling leading to improved coating quality and line speed

Short wave infra-red heating from Heraeus Noblelight has helped Demag Cranes and Components of Uslar, Germany to achieve extremely consistent quality of powder coating of electric motor housings. The infra-red system was also able to cope successfully with the limited space restrictions within the automated powder coating installation.

Demag Cranes and Components manufactures high value electric motors and various sizes of motor housings are coated with a high quality powder lacquer in an in-line coating plant. Complete with cooling fins, the housings presented a difficult powder coating challenge and this was made even more difficult because of the limited space available to carry out the necessary heating of the powder, both to melt it and to cure it.

To meet this challenge, Demag collaborated with the I-KON network, the specialist German organization for surface technology. Techniques such as convection ovens, gas infra-red and induction were rejected as the heating sources, because these techniques either required more space than was available or would probably require more maintenance. However, following successful trials at Heraeus Noblelight’s Applications Centre in Kleinostheim, it was decided to install electric infra-red, short wave emitters into a powder-coating plant built by Afotek GmbH, of Bad Hersfeld. Infra-red provides another significant benefit as powder is readily absorbed by short wave, infra-red radiation so that gelling is much faster than in a convection oven. Faster gelling improves the coating quality and permits higher line speeds. In addition, the powerful short wave emitters could operate efficiently within the limited space.

The powder coating plant is now operational. The housings are loaded on an orbital conveyor and are rotated, to ensure uniform lacquer-application, as they travel through the fully-automated, electrostatic powder coating plant. The applied powder coating is first melted and then heated, with the engine housing, to a temperature of 180° C by two infra-red modules, in a first heating zone. Two further infra-red modules in an adjacent holding zone then complete the cure of the coating. The emitters in the melting, heating and curing zones can all be individually controlled to vary power output according to the housing size.

Heraeus Noblelight specialises in the production and application of high quality energy sources covering the electro-magnetic spectrum from ultraviolet to infra-red. It has over 40 years experience in infra-red technology and offers the expertise, products and systems to provide efficient and effective solutions to drying, heating and curing problems throughout industry.