In datum association, can GOM Inspect ignore outliers by controlling the sigma?

[[Er...]]

Hello all,

For the purpose of associating (fitting) a datum plane to a real surface, GOM ignores the fitting method as specified in the Fitting Element dialog. Instead, it applies the rules of either ISO 5459 or ASME Y 14.5. (In the case of ISO: "Plane is outside the material, max deviation is minimized")

My question is: does the datum algorithm use the point selection as specified in the Fitting Element dialog?

For example: if the fitting element uses 3 sigma points -effectively ignoring the outliers- will the datum association algorithm use the same reduced number of points?

This pre-filtering would prevent the datum plane or system from being "lifted up"  by for instance a small burr. In plastic parts, small burrs or pieces of flash are often harmless to the function, so it would be a good thing if they can be ignored by reducing the sigma. I guess this is mainly useful to the plastics industry, because of the deformability of plastics.

 

[[Ch...]]

Hello,

nowadays the whole selection is used ignoring any additional computation constraints for computing the used fitting elements (and yes the sigma value is a computation constraint not a selection constraint). That means if you like to discard outliers you have to discard it in the selection (i.e. in the selected points visualized in red in the software) not in the computation parameters (as the sigma values) of the fitting element. Of course we are planing to introduce filtering function for GD&T inspection some day in the future but at the moment no major version for this feature is set.

 

Best regards

Christoph Schult

Edited October 20, 2021

[[Er...]]

Thank you Christoph!