Coating thickness gauge is a non-destructive measuring instrument, which mainly measures the thickness of non-magnetic coatings on magnetic metal substrates and the thickness of non-conductive coatings on non-magnetic metal substrates. When the device needs to test different materials, or the battery needs to be replaced, or the test ambient temperature changes, in order to reduce the measurement error, the user should do zero calibration on the zero-adjustment base as the reference. When the coating thickness gauge is zeroed, it is recommended to use the uncoated workpiece surface as the zeroing base.

Why do you have to use an uncoated workpiece for zero?

The main reason is that different test substrates have different physical properties of magnetic or electrical conductivity, which will affect the accuracy of test data. The GUOOU coating thickness gauge mainly uses the magnetic and eddy current principles to measure the coating on the metal substrate. 

Let's see the video as below :