Infra-red emitters speed coil coating process

Edited by the Engineeringtalk editorial team Sep 9, 2002

Infra-red heat dries reliably, rapidly and effectively and provides a high quality lacquer coating.

Coil coating is a modern coating process, which requires a highly developed drying technology.

Infra-red heat dries reliably, rapidly and effectively and provides a high quality lacquer coating.

Heraeus Noblelight is showing infra-red emitters which help to optimise the application of energy at the PaintTech exhibition in Sinsheim.

"They offer savings in both time and space", says Rudolf Lembke, applications specialist at Heraeus Noblelight, "and by shortening the coating process, capital- and production costs can also be reduced".

Coil coating, the strip coating process for sheet, has assumed great importance over the past few years.

Precoated coil strip is processed in virtually every industrial sector, from car bonnets, loading surfaces, shelves, identification plates and facade parts to washing machines and toasters.

A very fast but high quality drying of the coating is therefore essential, as the lacquering must be able to be worked satisfactorily during further processing of the coil.

In comparison with hot air drying, infra-red radiation saves both time and space and, unlike induction drying, it is suitable for non-conductive materials.

Infra-red emitters save energy and offer a high degree of process safety, as they can be switched on and off very rapidly and do not require long heat-up times.

Heraeus Noblelight has developed various emitters to ensure optimal lacquer drying: the CIR carbon infra-red emitter, with maximum power density at the optimum wavelength for water-based lacquer systems; short wave infra-red emitters, with powerful and fast response for all lacquering systems; and water-cooled high-power emitters which have peak power for especially fast production speeds and intensive heating, best for powder coatings.

Heat from infra-red radiation is applied directly into the material, without any transfer medium, and heating is significantly faster and more efficient than with hot air, which is fed from outside.

Infra-red modules are fitted as complete dryers or as pre-heat stations before a circulation oven.

In both cases they help to save space and energy in coil coating.

Infra-red radiation penetrates into the material and dries the lacquer film from inside outwards.

Skin- and blister formation on the surface is prevented and lacquer drying is speeded up.

The result is a brilliant surface quality.

Powder lacquer is finding increasing application in coil coating, as there is need for only one coating pass.

Gelling and curing of the powder takes place in one stage, while a coating with primer takes place before the actual lacquering.

Lacquer powder absorbs infra-red radiation very well and the powder heats up very quickly.

Rapid melting improves the lacquer quality and permits faster throughput speeds.

Heraeus Noblelight offers the complete range of infra-red radiation, from near infra-red NIR to medium wave carbon infra-red emitters CIR and provides advice on the selection of the right emitter for particular processes.