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General Surface Profile Callout

We have had a difference of opinion here at the shop that I work at and I'd like to get the opinion of some people that have been in this field for a while, because I know there are people out there that have a better understanding of GD&T than I do.
Let's say you have a CAD part model with a general profile tolerance ("Unless otherwise specified, all part features are subject to a surface profile tolerance zone of .020 with respect to the primary datum A, secondary datum B, and the tertiary datum C") and a specified thickness tolerance of +/-.010. You have a wall on this part that the model clearly shows does not have a constant thickness from one side to the other. Do you tolerance both sides of the wall according to the general profile tolerance, or do you hold one side to the general profile tolerance and then the other side to the thickness callout in spite of the fact that the thickness is not constant? Obviously if you hold both sides to the general profile tolerance, you have a potential for the thickness to run as high as +.020 if both sides of the wall were at top tolerance, but I don't see how you can hold it to a thickness tolerance when you don't have a constant thickness to hold.

Opinions? If you can back up your opinion with a specific aspect of the GD&T standard instead of "here's what I think" that would be even better...
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  • Pretty much, for a milled part, I would say the profile applies to "both sides" of stock, but if the profile is 0.020 (total) and the thickness is +/-0.010, then the thickness is a refinement tolerance, meaning you can't be -0.009" on both sides of stock because you would then be 0.018" thin.


    Bingo.

    You still have to meet both criteria simultaneously. So, you still have the predicament of which side is the "right" side.

    Like Matt, though, I work in automotive stamping, so generally we know that one side is the actual master, regardless of CAD thickness. And, we work with tailor rolled blanks, which can have variable thickness (which is shown in CAD, but doesn't exactly match it).
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  • Pretty much, for a milled part, I would say the profile applies to "both sides" of stock, but if the profile is 0.020 (total) and the thickness is +/-0.010, then the thickness is a refinement tolerance, meaning you can't be -0.009" on both sides of stock because you would then be 0.018" thin.


    Bingo.

    You still have to meet both criteria simultaneously. So, you still have the predicament of which side is the "right" side.

    Like Matt, though, I work in automotive stamping, so generally we know that one side is the actual master, regardless of CAD thickness. And, we work with tailor rolled blanks, which can have variable thickness (which is shown in CAD, but doesn't exactly match it).
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