Coating Thickness Gauge Calibration Requirements and Calibration Methods
The standard thickness sheet is a thickness standard used to verify the indication error and variability of the coating thickness gauge or to calibrate the coating thickness gauge. Calibration conditions of the coating thickness gauge, the temperature in the testing room: 20°C±2°C, the temperature equilibrium time between the thickness sheet and the gauge block: 2h; the humidity in the testing room: ≤65% and the warm-up time for the vertical optical gauge: not less than 15min. Power supply: 220 (1±10%) V, 50Hz.
1 Appearance
Requirements: There should be no scratches, bumps and other defects on both surfaces of the thickness sheet. Calibration method: Visual observation.
2 Effective area
Requirements: The area of a circle with a radius greater than 5mm should be marked on the uneven surface, and the area of the uniform surface thickness should not be less than 20mm×20mm. Calibration method: steel ruler measurement.
The average of 3 numbers.
Calibration method: measure the thickness of the standard thickness sheet with three equal gauge blocks and a vertical optical meter by the direct method or comparative method, clean the gauge block, thickness sheet, optical measurement anvil, and probe with aviation gasoline before measurement, and use it for calibration The radius of curvature of the measuring cap is not less than 20mm. When the measuring rod is lowered, the measuring cap should be lightly contacted with the standard thickness sheet by turning the branch to prevent impact on the standard thickness sheet. The calibration points are 5 points evenly distributed in the effective area (including Center point), for standard thickness sheets without effective area marks, the effective area shall be within a circle with the center as the center and a radius of not less than 10mm.
4 Uniformity error
Requirements: standard thickness sheet uniformity error. Calibration method, take the maximum difference between the thickness readings of each point and the average thickness value as the uniformity error of the standard thickness sheet, and the value shall not exceed the requirements in Table 2.
