The appropriate coating thickness is crucial in coating operations. Coating too thick not only wastes time and cost, but may also lead to coating rupture during the coating curing process. If the coating is too thin, the substrate may not be fully covered, and it is necessary to measure the coating thickness when the coating is still wet. For substrates that can only be measured using destructive methods, wet film thickness measurement is very useful. The wet film wheel is highly precise and convenient to use. It consists of three wheels, with a smaller diameter in the center and a larger diameter on both sides. Roll the wet film wheel along the wet film, and the center wheel will always come into contact with the film . The scale where the contact point is located is the thickness of the wet film. Wet film wheels can be measured on both flat and curved surfaces.