The faults of the coating thickness gauge for non-destructive testing mainly include unstable display of values, large errors, and failure to display numerical values. The causes of these faults include the instrument itself, the tested workpiece, and the influence of the natural environment. Below, we will introduce the methods to eliminate these faults.

The displayed value is unstable
The main reason for the unstable display of the coating thickness gauge is the special material and structure of the workpiece itself, such as whether the workpiece itself is a magnetic conductive material. If it is a magnetic conductive material, we need to choose a magnetic coating thickness gauge. If the workpiece is a conductive material, we need to choose an eddy current coating thickness gauge. The surface roughness and attachments of the workpiece are also reasons for the instrument's temperature display failure. The surface roughness of the workpiece is too large and there are too many attachments on the surface. The key to troubleshooting is to smooth out workpieces with relatively high roughness and remove any attachments, and then choose a suitable coating thickness gauge.

Too much measurement error
We have already introduced the reasons for the large measurement errors of coating thickness gauges in previous articles. The main reasons for the large measurement errors include: magnetization of the base metal, insufficient thickness of the base metal, edge effects, small curvature of the workpiece, excessive surface roughness, and placement methods of magnetic field interference probes.

Do not display numbers
The reason why the coating thickness gauge does not display numbers is to check whether the battery is fully charged. If it is found that the measurement still does not display values after confirming that the battery is fully charged.