MMC and LMC on a true position

[macattack0037]

Hey everyone,

Does this callout make sense? How can you have both an MMC and LMC that different with a hole tolerance of only +/- .0025? Something is not right here or am I missing this?

Thanks,
-M

 

[mkcski]

From my experience, I cannot imaging functional requirements that would require/accept LMC and MMC conditions simultaneously. But surprise me.

Certified Sr. GD&T Professional

 

[djhurayt]

I can kind of see what they are trying to do, but I don't know if its legal or not and the numbers certainly don't seem to make sense to me. Now having stated that, I am far from an expert on the subject, but like to read these threads and help my understanding of the subject. But what I see is:

It looks like they want the hole located perfectly when the hole is its smallest diameter (MMC) otherwise a .503 pin located exactly perfect in the mating part would not go in the hole. This makes sense, ???, I think.

And obviously if the hole was at its largest size (LMC) the hole could be located slightly off center. But allowing it to shift .012 when the hole can only be .005 larger than its smallest allowed size, doesn't make sense.

And what do you do if you hole is neither max or min, what allowed position shift is used.

 

[3DDave]

Each segment is evaluated separately. The component/part passes if it meets all the requirements.

 

[aniiben]

For me the call out looks legit and might be functional too. First position is concerned to some min wall/ thickness of something and the second position to the relationship between the holes / mutual relationship. I do not see a conflict or be an oxymoron.

 

[CheckerHater]

Agree.
MMC requirement is for 8 holes to behave as one (part probably looks like hinge of a sort).
LMC requirement is to make sure that "hole" is not too close to the edge of the part.


"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[drawoh]

macattack0037,

I agree with aniiben too. That is that symbol next to the diameter, and what standard are you working to?

--
JHG

 

[mkcski]

Everything posted above is conjecture. Could we see more of the drawing and some insight into the functionality?

Certified Sr. GD&T Professional