Precautions for Using Coating Thickness Gauge

1. Overburden thickness

The proportion of measurement inaccuracy of coating thickness gauge for products with too thin coating will increase significantly, because the measurement error of thickness gauge is generally 0.5 μ m. For measurement 25 μm, the accuracy of coating thickness gauge will be very low.

2. Thickness of substrate

Due to the working principle of thickness gauge, the thickness of metal substrate should be greater than 0.3mm.

3. Edge effect

The measurement too close to the edge is not representative. If the product is too narrow, it should be corrected on the uncoated material before measurement to improve the accuracy of measurement.

4. Curvature

Changes in the curvature of the specimen will affect the measured value. The smaller the curvature of the sample, the greater the influence on the measured value. For this instrument, when measuring specimens with a diameter less than 50 mm, the instrument shall be recalibrated on uncoated materials with the same diameter.

5. Rough surface

The surface roughness of base metal and coating has an effect on the measured value. This effect can be reduced by averaging multiple measurements at different locations. If the base metal surface is rough, the zero point of the instrument shall also be corrected at multiple positions on the corresponding metal material before coating.

6. Close contact between probe and sample surface

The probe of the thickness gauge must be in close contact with the sample surface, and the dust and dirt on the sample surface have an impact on the measured value. Therefore, ensure that the front end of the probe and the surface of the sample are clean during measurement.

7. Probe pressure

During measurement, the pressure applied to the probe has an impact on the measured value. The instrument has a constant pressure spring in the probe, which can ensure that the pressure applied by the probe to the sample remains unchanged during each measurement.

8. Perpendicularity of probe

The change of temperature will affect the probe parameters. Therefore, the instrument should be calibrated at approximately the same temperature as the operating environment. The instrument has good temperature compensation, and the temperature change has little effect on the measured value.