Calypsos profile callout not allowed.

[[Th...]]

I'm trying to do a plane profile on top plane to datums A and B but Calypso won't allowed it. If I change to "base alignment" or "alignment of feature" then it works. I don't know why?

PROFILE print.pngPROFILE.png

[[Ma...]]

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It looks like B is a cylinder perpendicular to plane A. This cannot function as a secondary (planar or clocking) datum. It wouldn't have any effect on the profile of the top plane anyway. In this case you can put datum A as primary, secondary and tertiary to satisfy the drawing requirements.

Also, unless I am looking at something wrong, it appears the direction vectors from plane A are 180 degrees off. Plane A faces downward doesn't it?

[[To...]]

Calypso does not process profile on standard geometry to a datum reference frame that is not fully constrained, i.e. all 3 datums. Profiles to 0, 1 or 2 datum features must use Free Form Surfaces option. This could be done by either creating a Free Form Surface feature on the Datum D plane, or re-calling the feature points from Datum D plane into a Free Form Surface Feature.

There is a school of thought that you could add the Datum B feature to the Tertiary Datum field. You will get a result but I don't believe this is a true, working alternative. One might say that if it passes in this condition, that it would more than likely pass with only 2 datum features.

I prefer to use Free Form Surfaces but I understand not everyone has the option.

[[Ch...]]

What you may be able to do is create a secondary 'Alignment" with just 2 datums; or if your Base Alignment only has these 2 datums, it should work.

As Tom said, DRF needs to be fully constrained.

Happy measuring!

[[Th...]]

Thanks for the insights guys.

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Yes, plane A face is sitting on the CMM table and I want to measure the table as plane A. I just haven't figured out a good way to go about it yet when offline programming.

[[To...]]

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One method is to extract the Datum A plane, which should have a space axis of -Z. Put some points on it. Change the space axis to +Z. This will change the vector direction of the points. Unfortunately, you can't drag the points beyond the perimeter of the plane but you can edit the X and Y values of each point.

Another method is to create a plane from the features list. Let's say the diameter of the part was 3". Open the newly created plane. Edit the X to -3 and the Y to -3. (These can be anything greater than the diameter of the OD.) Next, change Len1 & 2 to 6, basically making a 6" square plane centered at XY zero. By default it will already be a Z0 and the Space Axis will be +Z. Next, close the feature to lock it in. Next, re-open it, and add points or strategy to the plane. If you don't close it first, the nominals will change based on the strategy you created.