Mark and Don,
It took me awhile to digest what you have told me in your
last email. I have sketch a gage which achieve (I think)
what you have said.
Would you mind if I am asking you to take a quick look and
see if conceptual gage is right. ---see the attached
picture--
1.) Datum simulator A (size Ø.397) should be inserted
first and oriented with the slot to match the datum port
simulator C (virtual size Ø.075, here I am not 100% if the
virtual size is correct) and gage pin (size Ø.075).
2.) Slide the functional gage (this is the GO plug gage)
down—and if clear the profile being verified, the one side
of the profile is okay, is in tolerance.
3.) The other side of the profile to be checked with NO GO
gage pin (in red, size Ø.010.
Don, Thank you for the pages from one of yours books. It
is very very valuable. I appreciate it.
The sketch attached is in the files folder under
Pictures.pdf ---Follow-up questions 01-19-2012 sketch
-gage design to check profile---
--- In Y14-5_User_Group@yahoogroups.com,
"markfoster7700" <MarkFoster@...> wrote:
>
> Well, the answer to your question #1 is, yes, it is a
syntactically valid GD&T callout. But the obvious
follow up question for me to ask you is, is it a
FUNCTIONAL callout. If it is functional, then sure, you
should call it out that way, and it is completely valid.
If it is not functional, then we need to first explore
what really is functional so that our gage represents the
FUNCTION of the part, and not just whether or not the part
meets some arbitrary set of requirements.
>
> As for question #2, the answer is (sort of) yes. You
are correct that now the simultaneous requirements rule
would be in effect, and therefore you would only have two
checks. But the way that you described the gage working is
not quite correct. Your "Go" gage should FIRST, simulate
the datum reference frame -- that is, it should establish
the part in its correct (specified) coordinate system; and
then SECOND it should see if there is no material where
there is not supposed to be material (i.e. the "go" gage
should "go"). Then the "No-Go" gage should FIRST, simulate
the datum reference frame, and SECOND it should see if
there is material where there is supposed to be material
(i.e. the "no-go" gage should "not go").
>
> Your gage elements for simulating your datum features
on the part should be the virtual condition sizes of the
datum features, and must always go, and then by the amount
that the actual datum features have departed from those
virtual condition boundaries, you are allowed to "wiggle
the part" (i.e. take advantage of the datum shift
permitted by the MMB modifiers on the datum reference
frames of the profile callouts) until you can make the
"go" gage "go." And you should never be able to make the
"no-go" gage "go" no matter how much wiggling you do of
the datum reference frame.
>
> Hard to visualize with just typed words.....But do
you understand?
>
> --- In Y14-5_User_Group@yahoogroups.com,
"greenimi" <greenimi@> wrote:
> >
> > Mark
> > Thank you again for your replay,
> > I understand that if the component drawing
remain unchanged we need 4 separate checks to do, as per
your answer.
> > What about, if the component drawing for those 2
small surfaces will read
> > profile, .010, with A at M, C at M - D at M.
> > 1.)Is this a valid GD&T callout?
> > 2.)If yes, I guess the simultaneous condition is
implied and we need olny 2 separate checks:
> > - one check, for the GO side and the gage pin
should pass thru both side holes in the same time
> > - and the second check, for the NO-GO side and
the gage pin should not pass thru both side holes when the
slots touch the gage element.
> >
> > I have attached the revised print for your
review--
> >
> > Thank you again
> >
> > --- In Y14-5_User_Group@yahoogroups.com,
"markfoster7700" <MarkFoster@> wrote:
> > >
> > > Well, it may be a bit of a challenge to
determine good from bad with a gage, but I think you can
probabaly do it. The profile tolerances of .010 is a bit
tight for a "profile gage" but I think it might work.
> > >
> > > A couple of caveats and/or items to
consider: IF you are able to create gage(s) that will work
for you, you would need two separate gages, one for EACH
boundary limit for EACH surface in question -- that is, 4
gages total. You can probably be creative and make one
gage that has the "go" element for each of the two
surfaces on it, and another gage with the "no-go" element
for each of the two surfaces, but you still have 4
separate checks to do.
> > >
> > > Also, the gages that I am describing are to
check exactly what your drawing states. So if the drawing
requirements are not truly representative of the actual
function of the part, then you may end up with parts that
seem good by the gages, but don't work in practice, or
parts that seem bad by the gages, but work in practice. I
know that your sketch was incomplete by intent, but
personally I have my doubts as to some of the requirements
that are expressed. I have seen designs such as this for a
valve, and if that is what this is, then some of these
specs are a bit suspect.
> > >
> > > And, as with any "functional" gage, the
gage itself must have some tolerance, and depending on
which tolerancing philosophy that you choose to employ
("absolute," "tolerant," or "optimistic"), your gage
tolerance itself will come into play as to your risk level
of accepting truly non-functional parts or rejecting truly
functional parts.
> > >
> > > Hope that helps more than it confuses. Good
luck!
> > >
> > > Mark F.
> > >
> > > --- In Y14-5_User_Group@yahoogroups.com,
"greenimi" <greenimi@> wrote:
> > > >
> > > >
> > > >
> > > > Hi Mark and thank you for your relpay,
> > > >
> > > > Attached you will find a
sketch--incomplete by intent--
> > > > We are intrested to design a
functional gage to check the location of these 2 small
surfaces --profile-- The profile is bilateral as you can
see and they have MMC/MMB in DRF.
> > > > Can we check both limits--outer
profile and also the inner profile? Do we need 2
functional gages? I guess so. One is a go and the other is
a No-Go? What do you think? It is feasible?
> > > > Can we discern good parts from bad
ones?
> > > >
> > > > Any sugestions are welcomed.
> > > >
> > > >
> > > > --- In Y14-5_User_Group@yahoogroups.com,
"markfoster7700" <MarkFoster@> wrote:
> > > > >
> > > > > The short answer is, in theory,
yes. But the practicality of such a gage is questionable
depending on many factors. How big are the profile
tolerance values? If the value of the profile tolerance is
small, then the gage(s) will be very difficult, if not
impossible, to use and know for sure whether you passed or
failed the gage. Also, the very configuration of the basic
profile could make it impractical at best, and impossible
at worst, to gage the requirement.
> > > > >
> > > > > Do you have a drawing or a sketch
that you could post?
> > > > >
> > > > > Mark F.
> > > > >
> > > > > --- In Y14-5_User_Group@yahoogroups.com,
"greenimi" <greenimi@> wrote:
> > > > > >
> > > > > > Can a functional gage be
design to check the bilateral profile? DRF is at MMB.
> > > > > > Go gage to verify the outer
profile and a nogo gage to verify inner profile? Will this
concept work, at least in theory?
> > > > > > Datums are FOS at are at the
MMC----MMB in 2009-
> > > > > > We use Y14.5-1994
> > > > > >
> > > > > > Thank you
> > > > > >
> > > > >
> > > >
> > >
> >
>