we're facing a problem with a tube part which is approx. 500mm in lenght and consist of multiple diameters.
We have a concentricity on a diameter which is almost in the middle of the tube. Datum is A-C - two diameters - one on each side.
Now the problem is, that with every turn of the tube, concentricity is always different - as told, it shouldnt be.
Example:
Concentricity without moving the tube - 5 measurements - there's no deviation between measurements.
If we turn the tube 4 times for 120° - 1st and 4th measurements are identical.
Tried with different alignments - calculated concentricity is always the same.
If datum circles are not coaxial, your datums could be adding variation. If you'd like more specific details to help you resolve your concern, you gotta post napkin sketches and code.
If datum circles are not coaxial, your datums could be adding variation. If you'd like more specific details to help you resolve your concern, you gotta post napkin sketches and code.