When machining precision parts, roundness measurement method, two-point method and three-point method can be used for detection. The roundness method is to place the measured part on the worktable of the roundness meter, find the rotation center line, and make the probe of the roundness meter contact with the inner hole of the workpiece and rotate. Based on the sensor, amplifier, filter and measuring power circuit, accurate measurement results are finally displayed. If a specific contour map is output, the inscribed circle template can be used to take the radius difference between two tolerance circles on the same ship as the roundness error of a section. This instrument is applicable to parts with high requirements for measurement accuracy.
If the measured profile is an odd edge circle during precision part processing, roundness error cannot be measured by two-point method, but can be measured accurately by three-point method. Support the workpiece to be measured with a V-shaped bracket, and measure the large error caused by one cycle of product workpiece rotation with a micrometer as the roundness error of the section. Common V-shaped intersection angle α 60 degrees, 72 degrees, 90 degrees, 108 degrees and 120 degrees respectively. The three-point method can also be used for high-precision measurement in precision parts processing.
