Another Profile Question

[c_bearden]

There has been an on-going debate here at work regarding Profile and how you would apply tolerances to the Attached drawing...(SEE ATTACHED)
My way of thinking has always been the TOP of the composite Profile applys to SIZE and LOCATION and the Bottom portion applys to "FORM ONLY"
We are Burning this profile at EDM and it's approx 1" deep and on a 3° Angle.
The end result of the wire burn is a series of PLANEs and CYLINDERs, therefore I was interpreting the .003" profile to be .003" FLATNESS and .003" CYLINDRICITY and the Size was controlled by the top portion of the FCF (.010)......
I have sense realized I was wrong......:-)

I just wanted to see how everybody else "interprets" it.....The last time I started a thread about Profile it went for several pages...LOLOL....I am not trying to stir up a big debate, I just wanted to see if others were interpreting the way I did (FLATNESS / CYLINDRICITY ONLY)

[Matthew D. Hoedeman]

Individual points +/-0.005 to AGB, or a scan w/ PROFILE, FORM & LOCATION of +/-0.005. That's for the "top". Then a profile FORM ONLY of 0.003" for the entire thing (if it is only 2-D, then do a 2-D best fit alignment for this, if it is 3-D, do a 3-D best-fit alignment of all the points).

Best way to check it, make some CAD data, then use it to check the part. Planes & Cylinders..... not the best way to go about that IMO.

[Bruce Domer]

Here I thought the lower value of .003 in this feature control frame is to put a tighter control on its position to datum A, at first. But it does not call out A with the .003. If it was that way then it would tie the profile down to .003 relative to datum A. It also seems like this could mean that the total profile of the feature has to be within .003 of its basic shape. I am looking into my little book here and finally found composite tolerance but it only shows position and not profile. It says that it is used when the position is more important between all holes controlled by it than the actual position to the DRF. Is that what you ended up with? So as long as the complete profile is positioned within .010 to the DRF and the shape of the profile is within .003 of its basic shape it will be a good part. It seems like if the profile is all well within the .010 but any one point is more than .0015 off from its basic shape, it will then be a bad part. .003 = .0015 each direction parallel to the profile.

[vpt.se]

The callout is written as composite, yet if composite, we should see "A" as primary datum for the lower segment.
We are lacking datum "A" as a primary datum for the lower segment, so, is it meant as two separate callouts (with different datum structure) or as composite?

Don't assume, if in doubt, get clarification from the designer.

[frazz]

Remember to measure for success. That's a very pretty cluster all over the drawing, though. I definitely would have put all of my callout arrows criss-crossing the detail drawing like that, too.

[John Riggins]

Check this:

http://www.tec-ease.com/gdt-tips-view.php?q=189