Autocollimator to measure flatness
Time：2021-05-07 17:52:29 | 【
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In the flatness test, the principle of framing with lines is adopted. Measure the straightness of each sampling line on the tested plate separately, and then use the straightness curve of the sampling line to fit and construct the flatness of the entire tested plate according to the scribing principle and the corresponding mathematical processing method.
As shown in the figure above, take samples along the edge, diagonal, and centerline of the tested plate, and number the sub-tables according to a~h. Test the straightness of each straight line with respect to the starting point, and then use the intersection point (A~I) as a constraint to normalize each straight line, and then fit the straightness of the entire plate. When the constraint is normalized, the point with the most straight lines at the intersection point is regarded as the first constraint point. In sampling and marking, sampling can be carried out according to actual needs, but it must be ensured that the straight lines taken have intersection points. In order to accurately reflect the flatness of the flat plate as much as possible, the marking should be symmetrical and special sampling for characteristic points.
