Hello everyone
I’m measuring the roundness of some motor housings. The spec is 0.08. So far the results are within tolerance (0.052, 0.058...) but I’ve noticed that the results don’t repeat. I measured one part three different times and the results vary wildly. First I got 0.067, the 0.062 and finally 0.057. Why does that happen?
How I measure? I use SP25M, SM25-2 and the probe is 4x40mm. After the alignment I create a circle and I report the roundness of that circle.
Thanks.
EDIT: I was thinking that if I create a cylinder and report its roundness I would get a better result?
EDIT 2: The results vary only if I move the part. If I measure it several times without taking it out of the CMM the results are perfectly fine but if I move the part and then put it back, I get the varying results.
I’m measuring the roundness of some motor housings. The spec is 0.08. So far the results are within tolerance (0.052, 0.058...) but I’ve noticed that the results don’t repeat. I measured one part three different times and the results vary wildly. First I got 0.067, the 0.062 and finally 0.057. Why does that happen?
How I measure? I use SP25M, SM25-2 and the probe is 4x40mm. After the alignment I create a circle and I report the roundness of that circle.
Thanks.
EDIT: I was thinking that if I create a cylinder and report its roundness I would get a better result?
EDIT 2: The results vary only if I move the part. If I measure it several times without taking it out of the CMM the results are perfectly fine but if I move the part and then put it back, I get the varying results.
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