[Al...] Posted March 1 Share Posted March 1 Hello all, I describe my doubt: i have 3 datums, two circles and one plane (ABC). if i measure the elements regarding this datums with a secondary geometrical best fit allignment i have too much difference if i measure and set the datums individually. Why i have these difference, can both methods be trusted? I hope the pictures can explain better my question. Link to comment Share on other sites More sharing options...
[Cl...] Posted March 1 Share Posted March 1 I would use the CAD evaluation to show me where the plus and minus material conditions are for that surface. Then I would pick space points on the model in those areas and measure them. That should verify which result is correct. Link to comment Share on other sites More sharing options...
[Je...] Posted March 1 Share Posted March 1 Not quite enough information to make a complete assessment but I'm willing to bet that your DOF constraints aren't sufficient in the characteristic built DRF. A circle does not constrain any rotation and only 2 degrees of translation. The secondary alignment is cascading the base alignment in to apply full constraint of 6 DOF Try measuring Datum A as a cylinder instead of a circle which will constrain 4 DOF. Datum B may need adjustment in the same manner as well but its difficult to see based on the provided info. Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in