MMC Bonus calculation !

[Joe Chen]

Hello everyone
As shown in the figure, assume that the hole size is .344, the datum B size is 22.441, and the datum C size is .99, Is the position of the hole apply to MMC equal to .01(hole)+.01(datum B)+.20(datum C)=.40

 

[greenimi]

No it is not.
The indicated hole does not have bonus

 

[3DDave]

Variations in datum feature references do not allow extra variation in the location of the referencing feature relative to the datum reference frame.

Size-related modifiers applied to datum features allow for variation in the datum features to potentially allow the part to shift relative to the datum reference frame in a way to accept the referencing feature(s.)

 

[Wuzhee]

(M) behind the numerical value = Bonus tolerance
(M) behind Datum Feature Symbol = possible datum shift.

"Stop treating datum shift as bonus tolerance" - some TecEase guy cca 13 years ago.

 

[Joe Chen]

Thanks a lot, very clarity.