Add (M) to the concentricity/coaxiality FCF builder

Jörgen Andersson (vpt se) 8 years ago in Metrology Software / PC-DMIS updated by neil kay 4 years ago 9

ISO allows for the (M) modifier on concentricity and coaxiality, but I have yet to see this added to PC-DMIS. In order for my conc/coax evaluations to comply with the drawing, I must either do a bonus calculation, then an conc/coax evaluation with the calculated tolerance - or, use position to evaluate the conc/coax where the (M) modifier can be used.

Satisfaction mark by Jörgen Andersson (vpt se) 7 years ago

This is already being worked on by the development team and is logged as Jira ticket PCD20988


As Neil indicates, this is already in development as part of a bigger changes to GD&T, and is scheduled for the 2018 R1 release. In the meantime, the following workaround is suggested by the development team.

"Select Position rather than Concentricity and the modifier for the tolerance is available. Per ISO, Concentricity and Position are the same (Concentricity is a redundant tolerance in ISO and has been removed from ASME in the Y14.5 20XX Draft)"

They shouldn't add it. Per Y14.5 you can't have MMC on concentricity. Neil is correct about it being obsolete.

Engineers rarely know what they are talking about concerning to GD&T unless they have had specific training.

The best thing to do is just don't worry about the MMC when dealing with foolish cartoons.

Here is the text right out of Y14.5-2009

Of course it should be added - if PC-DMIS wants to be ISO-compatible. The workaround we use today is the one explained above, but for simplicity and ISO-compliance it should be added, which is why I vote for it to be added.

This will be supported in 2018 R1 when ISO 1101 is the selected standard. ASME does not allow modifiers for concentricity so (M) will not be supported when ASME is the selected standard.

We also added support for material condition modifiers to XactMeasure Coaxiality (ISO only) for 2018 R1.