Since its foundation in 1984, our company has been dedicated to photothermal coating measurement - a non-contact and non-destructive determination of the thickness of paint coatings based on thermal waves. The measurement principle is simple and is also known as the photothermal effect.
The photothermal effect has been known for over 100 years. It refers to the effect that materials can absorb optical radiation and convert it into heat.
A laser beam or LED radiation generates a slight heating on the paint surface. The heat flows through the paint layer and experiences a reflection at the base material. The thicker the layer, the longer it takes the heat to travel back through the coating. An infrared sensor determines the travel time and the electronics convert it into thickness. The process also works before baking, i.e. even with wet and powder coatings.
Depending on the application, the entire measurement process is completed after just 0.1 s, so that online measurements can be taken even at high product speeds of up to 200 m/min. The sensor achieves accuracies of up to ± 0.1 µm (ten-thousandths of a millimeter) from a distance of 250 mm for coating thicknesses of 0.005 mm to 0.2 mm. It tolerates distance variations of up to 100 mm.