inspection of tight tolerances

[lfw618]

Looking for some insight in how to effectively measure tight tolerances of less that +/- .0001" for parts up to about 3/4" and others up to 1.5" in diameter. We've been looking at some laser mics (Mitutoyo 503S and 9506), however looking at the size range needed the linearity error takes up almost the entire tolerance. And on top of that the repeatability adds another +/-24 millionths on there.

They also specify positional error which I don't entirely understand. Would that apply to in line measurement where the work piece is actually moving? Because that adds a good deal more error.

I know that it must be possible to measure this somehow, since for instance class XX pins have got about almost 10X tighter tolerance, and they must be inspected somehow, I'm just having trouble finding the right equipment.

Any advice/insight would be much appreciated. Thanks in advance.

 

[btrueblood]

I think you would remove the linearity error and probably the positioning error (not sure what that means either), by measuring a gage block near the object's size to calibrate, ideally before and after making the object measurement.