The failure of the coating thickness gauge of non-destructive testing mainly indicates that the indication value is unstable, the error is large, and the numerical value is not displayed. The causes of these faults come from the instrument itself, from the workpiece being tested, and from the natural environment. Below we introduce the methods to eliminate these faults.
The indication shows instability
The reason why the indication value of the coating thickness gauge is unstable is mainly due to the particularity of the 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 should choose a magnetic coating thickness gauge. If the workpiece is an electrical conductor, we have to choose the eddy current coating thickness gauge, and the surface roughness and attachment of the workpiece are also the cause of the temperature indication of the instrument. The surface roughness of the workpiece is too large and the surface attachment is too many. The main point of troubleshooting is to smooth the workpiece with a relatively large roughness, and to remove the deposit, and then choose the appropriate coating thickness gauge.
Too much measurement error
The reason for the large measurement error of the coating thickness gauge has been clearly introduced in the previous article. The main causes of the measurement error are: the base metal magnetization, the thickness of the base metal is too small, the edge effect, and the curvature of the workpiece is too small. The surface roughness is too large, and the magnetic field interferes with the placement of the probe.
Do not display numbers
The easiest reason for the coating thickness gauge to not display the number is to check if the battery is fully charged, and to determine if the battery is fully charged and if the measurement is found or not.