True Position MMC Callout

[VVPTD]

Good Morning! I am still very new to PC-DMIS and I am having trouble with the Xact measurement of a true position callout for a feature. The callout for the hole should read TP/ Ø.005 @ MMC/ A @ MMC but when I try to dimension it, it does not allow me to pick the MMC modifier for Datum A. Datum A is the plane that the hole lies on and is also my Z zero. Do I need to somehow dimension Datum A? Is there a way to add this modifier?

[AndersI]

A plane is not a feature of size, and cannot have MMC. Are you sure it's not a WIDTH feature that is marked as A?

[bfire85]

Are you able to provide a snippet of the dimension and Datum in question?

[DAN_M]

PC DMIS will not allow you to do something that violates the rules of GD&T. The feature control frame is invalid.

[VVPTD]

I will just put the dimension less the modifier. The print must be wrong because Datum A is the plane not a width. Thank you for the help and advice!

[A-machine-insp]

A snippet would help if allowed (ITAR/proprietary/export controlled).

[VVPTD]

Unfortunately I am not allowed to post anything. I appreciate the help tho!

[Wes Cisco]

Since no one has mentioned it, I will point out that in ASME GD&T, when the M in a circle symbol appears in the DRF (Datum Reference Frame) portion of the FCF (Feature Control Frame), it is NOT MMC but rather MMB. The same applies to the L in a circle. The difference between Maximum Material Condition and Maximum Material Boundary is significant. MMC adds to the allowed tolerance. MMB allows datum shift.

HTH & ymmv

[VVPTD]

Thank you for the explanation! I did not know about MMB.

[Paperback Rocker]

Widths are all the rage these days.