Frequently encountered problems in the use of coating thickness gauge probes
When repairing the coating thickness gauge probe, it is often found that the magnetic core is severely worn, and some can be said to be severely damaged. For example, the jewel core of the N1 head is often damaged and ballasted, and the arc core of the F1 head magnetic core is flattened or deformed.
First of all, it is normal for the probe to be worn out during use. However, if the user pays attention to its characteristics, its service life will be extended.
The ubiquitous problem is that during measurement, since the test is usually performed downwards, the user tends to press downwards more forcefully, which will easily cause the failure of the probe core over time. The correct way to use it is to gently press the probe to the surface to be tested when it is one centimeter away from the workpiece to be tested, because the probe has a built-in induction pressure spring in the design, and it only needs to be pressed down gently. On the other hand, during the repeated movement of the probe, it is easy to collide with other objects, and it is easy to cause damage to the probe. Therefore, if the working conditions permit, the probe can be fixed and the workpiece to be measured can be contacted with the probe. Reduce the bumping of the probe.
In another case, when measuring, every time the next point is measured, the measuring head must be lifted and not pulled flat, so as to reduce the wear of the magnetic core.
Finally, the probe must be kept away from strong magnetic fields, so as not to change the natural frequency of the probe and cause it to fail to work. Correct operation and use prolong the service life of the instrument.
Matters needing attention when using coating thickness gauge
a 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.
b base metal thickness
Check whether the base metal thickness exceeds the critical thickness, if not, use one of the methods in 3.3 to calibrate.
c edge effect
Measurements should not be made close to sudden changes in the test piece, such as edges, holes and inner corners.
d Curvature
Measurements shall not be made on curved surfaces of test pieces.
eNumber of readings
Often several readings must be taken within each measurement area since each reading from the instrument is not identical. Local variations in cover thickness also require multiple measurements in any given area, especially when the surface is rough.
fSurface cleanliness
Before measuring, remove any attached substances on the surface, such as dust, grease and corrosion products, but do not remove any covering substances
