Plane Profile - No Datum or FF

[[Ke...]]

Profile of Datum A (plane), with no applied Datum.
I have it set up with:
Feature: Datum A with LSQ
Datum(s): Datum A with Minimum Feature

...which is equal to Flatness.

Without Freeform as an option: Is this method correct?

[[Ma...]]

You can use Surface Profile for plane even without FFS.

[[Ke...]]

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Yes sir.
I'm using Surface Profile, but; without FF you need to apply Datum Feature(s)

[[Ma...]]

Well then apply plane itself 3 times

[[Cl...]]

[[Ke...]]

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So, there are two ways to go about it to get the same answer:

Load the Datums & go with the default Outer Tangential *but* select "Bi-Lateral - two results"

OR

(As I did)
Load the Datums & change the Evaluation Methods to "Minimum Feature" and leave the reporting as "Bilateral - one result"

Both results give the same value(s) as Flatness/Form.

I was second guessing myself, but it's good to know both methods.

Thanks Gents!

[[Ma...]]

I don't know how it is at you, but Profile is usually evaluated as one result - basically doubled worse deviation. If you used eval for plane as LSQ, then profile should get doubled flatness.

ASME i presume - for ISO is for all Gauss

[[To...]]

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The problem with using one result is that you don't know if your deviation is plus or minus or both without looking at a plot. By using two results, you can determine where the deviation is. It splits the tolerance in half but still show green or red, same at one result.

[[Ma...]]

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I know this and you can use it for your needs, but on report for customer must be what i said. Or it should be mentioned on drawings.

[[Ro...]]

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That may be true for ISO but not for ASME.

[[Ma...]]

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Well i have to apologize. I found some discussions about ASME and ISO and it looks like in ASME is reporting MIN MAX values ( but also some were to stick to ISO MAX*2 ).

And found one mention about reporting profile without datums for ISO - MIN MAX too.

I'll try to look deeper for this.

Every day is a learning day 😉

[[To...]]

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I've looked for anything regarding profile per ASME but have never found any mention on how to report it. As far as I can tell, ASME 14.5 only shows how to interpret the tolerance zone.

Anytime I've had a discussion with someone that said profile was the difference between min and max, they were a pc-dmis user.

Can you post any specifics?

[[Ro...]]

Hi Tom,
14.5.1M, 6.5 has the information that I'm talking about. Check out the Actual Value portion of profile calculation. Here's a snippet..

I've never understood doubling the max result, like ISO does. It gives you no meaningful information, IMO. Plus, you can get errant/strange results with unequal distribution profiles. If you have a profile of 10 U.002 and your result is -.002,+.003, your part is out of tolerance, yet 2x .003 is .006, which is in tolerance? It's just a bizarre way to report profile, IMO.

There's a lot of good stuff in Y14.5.1M. Most people just refer to 14.5 but there's a lot of really useful stuff in Y14.5.1M, IMO.