Precautions in Using Coating Thickness Meter

Ⅰ. Thickness measurement method of coating thickness meter

The coating thickness meter adopts both magnetic and eddy current thickness measurement methods, which can non-destructively measure the thickness of the non-magnetic covering layer (such as aluminum, chromium, copper, etc.) on magnetic metal substrates (such as steel, iron, alloy, and hard magnetic steel, enamel, rubber, paint, etc.) and the thickness of the non-conductive coating (such as enamel, rubber, paint, plastic, etc.) on non-magnetic metal substrates (such as copper, aluminum, zinc, tin, etc.). 

1. Magnetic method. When the measuring head of the thickness gauge is in contact with the covering layer, the measuring head and the magnetic metal matrix form a closed magnetic circuit. Due to the existence of the non-magnetic covering layer, the magnetic resistance of the magnetic circuit changes. The thickness of the covering layer can be derived by measuring the change.

2. Eddy current method. The high-frequency alternating current of the coating thickness meter is used to generate an electromagnetic field in the coil. When the measuring head is in contact with the covering layer, an eddy current is generated on the metal substrate and a feedback effect is generated on the coil in the measuring head. The thickness of the coating can be derived by measuring the feedback effect .

Ⅱ. Matters needing attention when using coating thickness meter

1. Make sure that the probe is perpendicular to the outer surface of the test when measuring.

2. Keep the pressure stable during measurement.

3. When conducting the test, pay attention to the metal magnetic properties and surface roughness of the standard substrate should be similar to that of the test piece.

4. When using the eddy current coating thickness gauge, pay attention to the influence of the curvature of the test piece on the measurement.

5. Before measuring, pay attention to whether there will be magnetic fields in other electrical equipment around.

6. In using the thickness gauge, pay attention to the critical thickness of the base metal when testing. If it is greater than this thickness, the measurement will not be affected by the thickness of the base metal. 

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