Conditions and Solutions for Accurate Data Obtained by Portable Coating Thickness Gauge
In actual use of the portable coating thickness gauge, in order to obtain accurate measurement data, certain conditions must be met:
1. Base metal properties
For the magnetic method, the magnetic properties and surface roughness of the base metal of the standard piece shall be similar to those of the test piece base metal.
For the eddy current method, the electrical properties of the base metal of the standard sheet shall be similar to those of the test piece base metal.
2. Base metal thickness
Check whether the thickness of the base metal exceeds the critical thickness. If not, one of the methods in 3.3 can be used for calibration.
3. Edge effects
Measurements should not be made close to sudden changes in the test piece, such as edges, holes and inner corners.
4. Curvature
Measurements shall not be made on curved surfaces of test pieces.
5. Usually, since each reading of the instrument is not exactly the same, several readings must be taken in each measurement area. Local variations in cover thickness also require multiple measurements in any given area, especially when the surface is rough.
6. Surface cleanliness
Before measurement, any attached substances on the surface should be removed, such as dust, grease and corrosion products, etc., but do not remove any covering substances.
