Whether an ultrasonic thickness gauge needs to remove the coating before measurement depends on the thickness and composition of the coating.
An ultrasonic thickness gauge measures the thickness of a material by emitting ultrasonic waves and receiving the reflected signal. The thickness and composition of the coating (such as paint) will affect the ultrasonic signal, thereby affecting the accuracy of the measurement results. Specifically:
Coating thickness: Thicker coatings may weaken the strength of the ultrasonic signal, causing the instrument to not receive enough reflected signals, thus affecting the measurement accuracy. Coating composition: Certain components in the coating may react with the ultrasonic signal to generate interference signals, affecting the accuracy of the measurement results. Metal particles: If the coating contains metal particles, these particles may become a reflection source for the ultrasonic signal, causing the measurement result to be too large or too small.