Angularity

[[To...]]

I have an angled plane (Datum C) which has an Angularity call out to A and B. In the help, it states the nominal angle is from the feature to the first datum, which happens to be 90°. It appears to not consider the other angle. If I use datum B as the Primary, then the nominal angle of the feature appears and the results are more realistic.

Is this a case where I should ignore Datum A and just use Datum B?

Angularity 1.jpgAngularity 2.jpgAngularity 3.jpg

[[Cl...]]

I would say yes, because of B's orientation relative to C, it make perfect sense to me.

[[To...]]

I guess I didn't read ALL of the help, correctly. So, I should ignore what is shown on the drawing and give them the results they are looking for....

Angularity 5.jpg

[[Me...]]

If -A- is the Primary then that's the angle you report. B is stopping a rotational DOF as the secondary. Not sure why your result is so out. Have you tried rotating your coordinate system so that C is 90 deg to A and then checking it?

[[To...]]

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The angle is relative to B, so I'm guessing the drawing should have been to B then A.

[[SH...]]

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Wonder, in your post there is always something new to learn .

Don't ignore the drawing, you should discuss with your customer.

[[Ri...]]

They are probably wanting to use A as a constraint. If you constrained B to A would you get what you are looking for?

I see this with Runouts all the time.

[[To...]]

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That was the first thing I considered when I thinking about using B for the Primary.

[[Ma...]]

I actually have a czech translation so i don't know it's exact name, but wouldn't be enough angle between elements?

[[To...]]

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No. Angularity is an orientation control and uses a tolerance zone similar to parallelism and perpendicularity. The angle is BASIC

I've actually seen an argument for using one symbol for all 3 and just specify the angle relation ship between the feature and the datum...

[[To...]]

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That's fine if you address it when you're quoting it but at final inspection, it's a little too late. Sometimes, your customer is not the final customer.

[[Ri...]]

Yeah. Angularity is not a tolerance on the angle.

[[Ma...]]

Thanks, I just realized it 🙂 We have translation misunderstood. Then you have to come with another strategy. Maybe rotated coord system and recalled elements? Or if it help some 3dline as 2nd base to rotate to desired angle measuring?

[[Me...]]

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I guess I'm misunderstanding.

But, if there is a basic angle drawn that's to B instead of A, it doesn't override the FCF. The FCF takes precedence. The same as if someone daisy chains a bunch of holes with basics center to center, when the actual hole locations are all to a common datum.

[[Br...]]

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Right and actually there is a basic to A. It's just implied 90°. Implied 90° basics are a fundamental rule of Y14.5. Can you imagine having to put every 90° angle on a drawing? Every position tolerance of a hole that is perpendicular to the primary datum feature would have to include 90° basic angles to define their orientation relative to the DRF.

[[To...]]

I think some of you are missing the point. I understand the hierarchy of a datum reference frame but in my example, when you follow it in an Angularity characteristic, i.e. A = Primary and B = Secondary, Calypso creates a tolerance zone equivalent to 2 parallel planes that are perpendicular to the primary and parallel to the secondary, when clearly, the tolerance zone should be parallel to the feature.

If I use B as the primary, the tolerance zone is controlled by B, but it reads the nominal angle of C and rotates the tolerance zone by that angle. In order for A to still "act" as the primary, B would need to be constrained to A, like Richard suggested.

An option similar to a position of an angled hole, where you need to use the Special button to rotate the coordinate system, might be a good fix.

Angularity 5.jpg

[[Jo...]]

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Does Calypso "see" the angle as 2d ? For example if the part error was off in two vectors compound, would evaluating each Datum separately still produce the worst case condition ?

[[To...]]

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Good question. I just tested by importing points with 1 projection angle skewed 5° and another with both angles skewed 5°. Results reflected both variations.

Update to something I posted earlier. I turned on CAD Eval and activated Tolerance Frames. It shows the frames being normal to the feature (C) but the results are calculated in 2 different ways. The data points on the 2 screenshots is using 0 dispersion.
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Angularity 6a.jpgAngularity 6b.jpg

[[An...]]

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[[An...]]

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[[To...]]

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What do you think about this option?

angularity 7.jpg

[[An...]]

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[[Br...]]

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I think you found the ticket.

[[To...]]

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I don't understand your last statement. Why is a mixture of both not helpful? I would assume both directions should be evaluated. Your method of using a theoretical 40° plane seems like it will work, as well as mine. However, for you Andreas, I will test both methods.

[[Ma...]]

Tom - it seems like base coord of element is used. So for angularity between B and C must be used B as primary ( ie using Z axis for rotation ) - if A used as primary, then Y or X axis is used for rotation. So if you want to measure 90° you should rotate plane A by angle 40° ( or what is on drawing ), but i didn't tested it.

At least this is what i see from numbers what you sended.

Edit: 24.9.2020 6:55
Ok i did some tests and rotation of primary plane does not affect calc.

So for measuring 90° you must use theoretical plane/line/3d line and put right angle to correct axis.