Default nominals ok with profile?

[[RP...]]

I haven't ran into an issue with lengths but I'm having trouble reading a profile accurately.  Are my feature nominals affecting the overall measurement?  I noticed the actuals are referring to the strategy location.  Should I be changing the nominals and moving my strategies?

Images are from simulation.  A live run is always measuring a couple tenths over.

 

[[Cl...]]

It looks like those are just the difference between the plane's origin and the actuals. I see your referencing the profile back to the base alignment.

Is the BA using the datums in the DRF? Or is it profile to no datums. In which case you'd want to use "No Datum Reference"

[[Ma...]]

I see no problem. Nominals and actuals are as they should be. Actual size of a plane is defined from measured points - and since you have that plane in X direction, then only X nominal and actual is the same.

In Calypso there are many things which needs to have deeper knowledge - for example perpendicularity on plane. Calypso don't know circular planes.

[[RP...]]

Thank you for the responses!

The print is saying .002 max profile to -A- and -B-.  The alignment is using 3 datums ( -A- -B- -C-) to establish the base alignment.  -A- is a cylinder with its axis in Y.  -B- is a plane at the start of the cylinder in -Y.  -C- is a plane perpendicular to -B-, and directly in +Z.  

The profile incudes another plane opposite of the one pictured, datum -A- would be in between them.  Would a regular profile like I have it work fine?  Or should I be utilizing a geometry best fit alignment?

[[Cl...]]

Use only Datum's A & B in the profile characteristic. When datums are involved, you cannot use the GBF.

Edited July 11, 2025

[[RP...]]

I get an error if I only use the two datums.  

The programming level 3 book shows a GBF using datums?  Am I misunderstanding the information?

[[RP...]]

Would creating a secondary alignment with just datums -A- and -B- work?

[[Cl...]]

Are you using the newest rev of Calypso with the new GD&T characteristics? I don't have Calypso 2025.

I was told by several Zeiss applications engineers that the GBF can only be used when no DRF is given.

[[RP...]]

Calypso 2023.  

Page 31 of the Zeiss Programming Level 3 book shows an example of a profile of several surfaces to composite of profile tolerance.

I had 3 profiles giving me trouble and they became conforming after using the GFB method.  

[[Ma...]]

I am  not sure if B is enough for stopping rotation.

Anything you won't fill in an alignment will be taken from parent value - so using A-B will put missing from base alignment.

I would make and alignment from A and intersection of A and B to have an origin. Then using C in bestfit with parent alignment from previously and allow only rotation.
This would be close enough.

I have no experience with manually filling partial datums so i can not help there.

[[RP...]]

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Could you elaborate on Calypso doesn't know circular planes?

[[DW...]]

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 Unless you select "No datum reference frame" in the profile window, Calypso needs to see all three blocks filled in. So you would put A in the first one, B in the second one, and B in the third one. Then it will calculate. 

[[Ma...]]

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For this - imagine perpendicularity. This you can try:
Plane perpendicular to axis ( cylinder ) - set plane's angle A1 to 5° - this will give you a  value. Now rotate plane in cylinder axis and look for value.

[[Ja...]]

Are you sure that feature is a plane? It doesn't look flat to me.

[[Cl...]]

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Edited July 14, 2025
Mistake

[[Cl...]]

This must be fairly new. I'm using 2020 (simulation). It allows me to use only two datums.