explained how calypso calculate Perpendicularity

[[K...]]

I developed a plain 80mmx80mm as datum B which is measured by 20 hits within Ø124mm zone and in the same vector direction. Flatness is 0.028mm.

I developed a 3-D line as a datum A by using 3 circles, length is 16.5mm.

All circles roundness and locations are within 0.011mm.

When I define Perpendicularity of 3-D line w.r.t to datum B, I found 0.045mm But if I defined datum B perpendicularity wrt to datum A (3-D Line), my result is 0.200mm.


May I know the reason.

Thank you

[[SH...]]

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What is the diameter of the circles?

IMG_20200830_185436.jpg

[[K...]]

Ø of circles are 203 mm.

[[K...]]

Can we use datum feature for evaluation OR define datum feature 2nd time and then evaluate?

[[Ri...]]

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The ratio of axis length to diameter of your cylinder is too short to use as a Datum that is why you are seeing huge difference in results.

You are getting projection error which is very common.