Flatness or Profile of a Line?
Flatness or Profile of a Line?
(OP)
Hi everyone... Have a look at the attached .jpg please.
Where I work, this is a standard view of a metal housing used to hold a small electrical component that we design and manufacture here.
My question is... Why on Earth would you want to use the profile tolerance on the bottom surface instead of another flatness tolerance? This housing simply sits in a larger housing where it is connected to the outside world. The inner housing is necessary because the electrical component I mentioned need to be hermetically sealed and thermally controlled.
I could even understand using profile of a surface over profile of a line... Am I missing something? Or is 'the way we've always done it' now 'the way we shouldn't do it anymore'?
Thanks,
Mod
Where I work, this is a standard view of a metal housing used to hold a small electrical component that we design and manufacture here.
My question is... Why on Earth would you want to use the profile tolerance on the bottom surface instead of another flatness tolerance? This housing simply sits in a larger housing where it is connected to the outside world. The inner housing is necessary because the electrical component I mentioned need to be hermetically sealed and thermally controlled.
I could even understand using profile of a surface over profile of a line... Am I missing something? Or is 'the way we've always done it' now 'the way we shouldn't do it anymore'?
Thanks,
Mod





RE: Flatness or Profile of a Line?
KENAT,
Have you reminded yourself of FAQ731-376: Eng-Tips.com Forum Policies recently, or taken a look at posting policies: http://eng-tips.com/market.cfm?
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Flatness or Profile of a Line?
I'm studying my GD&T, so I don't know everything there is to know about this stuff, but doesn't profile of a line only control that one visible edge of the part when applied to that view?
RE: Flatness or Profile of a Line?
http://tec-ease.com/tips/january-06.htm
They have info on most of the GD&T call-outs and where I go whenever I get confused :D
RE: Flatness or Profile of a Line?
So the way it is used in the attached image makes no sense.
RE: Flatness or Profile of a Line?
Dave D.
www.qmsi.ca
RE: Flatness or Profile of a Line?
Powerhound, GDTP T-0419
Production Manager
Inventor 2009
Mastercam X3
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II
RE: Flatness or Profile of a Line?
RE: Flatness or Profile of a Line?
Specifying the profile of a line control on the edge in the view does NOT mean just that one line element; it means each line element on that bottom surface, and each line element is independent of every other line element on that surface. That brings me to point #2; without a datum reference, a profile control (line or surface) controls size (of an enclosed boundary) or form. As a result, it would just mean straightness on that bottom surface.
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: Flatness or Profile of a Line?
And thereby independent of the size of the part? So no bonus tolerance?
RE: Flatness or Profile of a Line?
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com