Applying Composite Profile Tolerance with Calypso

[[Ca...]]

Hello,

I am trying to apply a composite profile tolerance across three planes. I have a sample part and each plane individually is well within its 1.0mm profile tolerance and I believe that the composite profile control is in spec as well. I am just stuck on how to prove that using my Zeiss. I have been able to use the "best fit" feature to apply composite positional tolerances in the past, but I am not seeing similar features when working with profiles. See picture below. Does anyone have a reccomendation on how to apply this in Calypso?


Thanks,
Carl

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[[Ma...]]

I have never seen a composite profile tolerance where the same DRF is used for both the top and bottom with different tolerances. Generally the bottom only controls orientation, or partial location. If the DRFs are the same what would be the reason for the different tolerances?

[[Ro...]]

The first tier of the callout is checked using a fully constrained datum structure to A-B-C, unless some degree of freedom is free, in which case you would best fit that DOF.

The second tier releases the translational constraints, so it's a best fit allowing the part to translate but not rotate.

You won't be able to get the MMB on Datum -C- Calypso will not do that.

You need to create the best fit alignment using something like geometry best fit and releasing the translational constraints in the order of precedence of the callout. You can even build alignments on alignments if you want to incrementally constrain the geometry. Then use that alignment in your profile characteristic instead of inputting the datums in the characteristic.

[[Jo...]]

I'm not sure how it applies to the features in your case, but it helps me understand intent. I notice there also is a tertiary modifier M .... I'd have to brush up on simultaneous requirement for Profile.. Anyways here is ASME

comp prof.JPG

[[Jo...]]

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Would the second tier be a total width .5 zone in which 3 planes were coplaner and flat ? The lower tier is form control of 3 as a continuous feature . The upper tier locates in part.

[[Ca...]]

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I did try creating a theoretical feature with recalling all three planes on the same feature. When applying a profile tolerance to the theoretical feature in reference to ABC it came out to 1.2mm - way over tolerance. Each of the three individually in reference to ABC were about 0.1mm profile tolerance, so I think its reasonable to assume they would be in tolerance to each other but I am applying incorrectly making them one plane.

[[Ca...]]

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So you are suggesting that I create an alignment for each plane and then create a profile tolerance for each individual plane in reference to the other two alignments? In this case I would have 6 total profile tolerances for the 0.5mm section of the composite frame.

profile 1 in ref to alignment 2
profile 1 in ref to alignment 3
profile 2 in ref to alignment 1
profile 2 in ref to alignment 3
profile 3 in ref to alignment 1
profile 3 in ref to alignment 2

[[Ca...]]

For what its worth I stumbled on this solution while looking for other examples on the internet - it was similar to what I am dealing with so I gave it a try. You can create a geometry best fit alignment and select the 3 planes that are apart of that fit. You can then use this alignment as your datum reference plane for a profile tolerance. I will use this as my first go around and go ask the engineer who applied the composite what his intentions were and if this will satisfy them. Thanks everyone for your input.

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