How to judge whether the accuracy of measuring instruments meets the standard?

Determining whether the accuracy of the measuring instrument meets the standard is an important prerequisite for ensuring the reliability of the measurement results.

Verification using standard gauge blocks

A gauge block is a measuring instrument with known precise dimensions and is the most common method of verifying the accuracy of a measuring instrument. Select several standard gauge blocks of different sizes, measure on the instrument, compare the measured values ​​with the standard values, and calculate the error.

Repeatability verification

Measure the same workpiece multiple times under the same conditions (more than 10 times are recommended), and calculate the standard deviation of the measurement values. Repeatability accuracy should not exceed 1/3 of the instrument's nominal accuracy.

Reproducibility verification

Different operators measure the same workpiece at different times and compare the consistency of the measurement results.

Compare with higher precision instruments

Measure the same workpiece on the instrument to be tested and a higher-precision instrument (such as the standard equipment of the Metrology Institute), and compare the results.

Judgment criteria

According to the accuracy index marked in the instrument manual and combined with the data obtained by the above verification method, determine whether the instrument accuracy is within the allowable range. If out of range, calibration or repair is required.