Unilateral Profile Tolerance with Bonus 6

[DRWCA]

Curious about the interpretation of the unilateral tolerance zone in the following example. As A departs from MMC, does the bonus tolerance applied to the profile control now allow for removal of material, or is the implied 'outside only' condition preserved, ie. would the implied profile callout at a diameter of 14.8 be |0.5 U 0.1| or |0.5 U 0.5|?

Or perhaps the better question - is this even a valid callout?

 

[axym]

Here's the corrected diagram:

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca

 

[Tarator]

Evan,

In the image on the right, you are declaring/defining the cylinder as a surface (non-FoS) or as an irregular FoS (type A), right? And if so, the profile call-out would only be valid for 2009 (and 2018) version because in 1994 version the (M) after A would be MMC and could only be applied to a FoS, is that right?

 

[pmarc]

In the image on the right, you are declaring/defining the cylinder as a surface (non-FoS) or as an irregular FoS (type A), right? And if so, the profile call-out would only be valid for 2009 (and 2018) version because in 1994 version the (M) after A would be MMC and could only be applied to a FoS, is that right?

The reason why the profile callout is not valid per 1994 is that there is no (U) modifier defined in that version of Y14.5.

Since maximum material condition of datum feature A is determinable, A can be referenced at MMC in the profile feature control frame. To me this is how "extending or interpreting some statements in the standard" works.

 

[greenimi]

In my opinion the VALID scheme is VALID (sic) regardless of the standard and the NON VALID scheme is incorrect do NO matter which version of Y14.5 is used (1994, 2009 or 2018), but:
in 1994 the VALID scheme shall use phantom lines that are drawn parallel to the true profile to indicate the tolerance zone boundary (outside of material) and circled U and 0.1 after it should be removed from the profile FCF.
A(MMC/ MMB) in the DRF of FCF is valid "as is" in 1994,2009 or 2018.

 

[axym]

Tarator,

I'm not sure if the cylinder needs to be declared as a particular type of feature of size, but I think you're right that this would only be valid for 2009 and onwards. I would lean towards thinking of it as a "mathematically defined surface" that happens to be nominally cylindrical.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca