Default Profile Evaluation DOUBLES my Results.. Why?

[[Si...]]

Hi,

So if I were to check at the default Bilateral evaluation of this, I get .0011

If I check Min Max I get Min: .0001 Max: .0005

See attachment, I have it sitting as shown in the Drawing, top right section.

In everyone's experience with Calypso and Profiles, what would the basic eval be?

I am new to Profiles, and I hear Calypso has slight issues with them as well. Any guides besides the cook book which doesn't have much in it.

Profile.png

[[Aa...]]

It's doing exactly what it's supposed to do. That .0005 tolerance is bilateral - plus or minus .00025. It doubles the result so that it would be an apples-to-apples comparison with the tolerance. In other words, your max is .00055, which would satisfy a bilateral profile of .0011.

[[Me...]]

It depends on the standard. ASME doubles the deviation. ISO reports the min/max. The best way to report it, IMO, is as a Min/Max. With ASME reporting you can have a result number that is within the tolerance called out, but actually out of tolerance because most of the deviation is on one side of the profile on a bilateral callout.

[[Aa...]]

Any chance you could site your sources? I don't believe ASME or ISO give any reporting requirements. I don't know all the ins and outs of ISO, but from what I've seen in ISO 1101, profile tolerances by default are exactly the same as in ASME (with the exception of radial vs. sharp corners on the tolerance envelope).

"The tolerance zone is positioned symmetrically from an ideal feature unless otherwise indicated. The tolerance value defines the width of the tolerance zone. This width applies normal to the specified geometry unless otherwise indicated."

Min/Max can be a much more helpful way of reporting, but be sure you enter the tolerances correctly. (In the OP's case, that would be plus or minus .00025, if they're working in inches.)

[[Er...]]

You are correct Aaron. Profile deviation according to ISO is biggest deviation from nominal times two. Difference between max and min deviation is simply form.

Robert, you have probobilly confused profile tolerance with form.

Silvio, what are the issues you have heard about calypso and form?

[[Me...]]

ASME 14.5.1M
(c) Actual value. For both unilateral and bilateral
profile tolerances two actual values are necessarily
calculated: one for surface variations in the positive
direction and one for the negative direction. For each
direction, the actual value of profile is the smallest
intermediate tolerance to which the surface conforms.
Note that no single actual value may be calculated
for comparison to the tolerance value in the
feature control frame, except in the case of unilateral
profile tolerances.

ASME contradicts itself, in that it reports double the total deviation, as shown in the OP's post, yet that number doesn't necessarily represent the actual profile pass/fail criteria. That's what I was trying to say in a roundabout, poorly worded, convoluted way. 😃

[[Me...]]

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Profile can control Size, Form, Location, & Orientation. A profile tolerance with no datums referenced is form only.

[[Si...]]

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The issue I came across when starting to get into Profiles with Calypso is that

1: Calypso requires 3 Datum's to get a result. Most of my drawings I go off of have Profile to itself, or 1-2 Datums. So the Tertiary datum being required is my issue at times.

2: In Calypso when at the Characteristic screen and it asks for the Nominal, Max and min tolerance.. how can I add in decimal places. Example is with the attached drawing. I cant make the Min or Max tolerances beyond 0.0000 it just rounds. (I know this has an option but I have a part with a +/- 0.00025 and it just rounds to .0003)

3: I don't have Free form or curve lol....

[[Si...]]

What exactly does Inward / Outward to infinity do??? Should it ever be used??

[[Ca...]]

I've only ever used the Inward/Outward for defining BOUNDARY locations on features like complex slots, or cutouts.

[[Me...]]

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Create a Geometry Best Fit alignment with the features selected you want a form only profile of. Under Evaluation Constraints make sure Best fit and all the DOF are selected. Create a profile characteristic, select your feature, and select the Geometry Best Fit alignment as your Datum Ref Frame. It will populate the Primary datum box. No need to select Secondary and Tertiary because the BFG alignment has already taken care of the fitting.

[[Er...]]

No Robert, without datum its free to translate and rotate. So yes its not controling location or orientation. But its still the biggest deviation, positive or negative times two. Form is distance between max and min deviation.

There is a difference between form and profile of a surface/line.

Ok Silvio, without free form its kind of crippled. Otherwise in my opinion Calypso i pretty good at it. (except 6.6, its only good at being bad. I really hope 6.6.16 will fix it)

[[Me...]]

I agree with all that, Eric. I was just talking about reporting profile, not form.

[[Er...]]

Now Im confused.. 😱

Well in that case, I guess.. Merry christmas. 😃

[[Me...]]

I think it's just a terminology misunderstanding and my inability to make a cohesive point. I was only referring to form as in what the profile is controlling, not reporting form itself.

I've probably confused you even more. My work here is done. 🤣

Merry Christmas! 😃

[[Öz...]]

Hello All,

I just want to add this picture to this topic. It can be helpfull for everyone.