Coatmaster Flex - Functionality and Measuring Principle

coatmaster Flex
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4. Functionality and Measuring Principle
The coatmaster® works according to the principle of advanced thermal optics (ATO). The surface of the
coating is heated with a light pulse. After brief heating by a few degrees, the surface is cooled by heat
conduction to deeper areas of the coating and the substrate. The cooling process on the surface
depends on the thermal properties of the coating and the substrate. The thinner the coating, the faster
the surface temperature decreases, provided it has a lower thermal conductivity than the substrate.
The thickness and thermal properties of the coating are derived from the dynamics of the surface
temperature.
Figure 1: Illustration of the measuring principle
① Flash lamp
② Pulsed heat input
③ Coatings
④ Substrate
⑤ IR radiation
⑥ IR sensor
Generally, coatings have a very irregular surface. Powder coatings prior to curing have an even rougher
surface but can nevertheless be measured with the coatmaster® Flex. The properties of this roughness
are influenced by various factors, such as pre-treatment, the type and roughness of the substrate, the
type of coating (e.g., particle size, distribution, and chemical composition), and the exact conditions
(temperature distribution, baking time) during curing. The diagram below shows a microscopic sketch
of this roughness. The ATO automatically compensates for the roughness described above, using an
optical averaging process. This allows a reliable determination of the coating thickness, even with
changing parameters.
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Figure 2: Sketch of surface roughness of a powder coating after curing
① Substrate
② Coating