【转帖】profile tolerance regarding to other profile as datum

yang686526

profile tolerance regarding to other profile as datum
before anything i have to say that i am beginner in gd&t, and it is really interesting, i  am a mechanical designer and recently i have designed some components for certain stamping process, as you understand accuracy is critical and some surfaces must be controlled using profile tolerance, to illustrate the situation, attached you can find a pdf drawing with one of the components which i recently have designed, in this component the outer profile should be controlled as is stated, but i have an other very important profile(showed in 鈥淒etail b鈥? which shall be controlled by the profile represented by 鈥淒atum d鈥? and it has to be controlled all around by this boundary. i am not sure if this kind of tolerance is correct, or even if will be interpreted as my intend.
i don't see a drawing standard referenced on the drawing.  what standards do you draw to?
kenat, probably the least qualified checker you'll ever meet...
i am using ansi as dimensioning standard.
your datums b, c, & d are redundant.  in asme y14.5 - 1994 section 4.4.2 - parts with cylindrical datum feature.  a cylindrical feature is always associated with two theorectical planes intersection at right angles on the datum axis
heckler   
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this post contains no political overtones or undertones for that matter and in no way represents the poster's political agenda.
so let me be more specific.  as regards gd&t are you using asme y14.5m-1994 or an earlier version?
kenat, probably the least qualified checker you'll ever meet...
yup - heckler is correct about your datums. datum a is good and then you need a cylindrical feature for the secondary datum. it could be the od or id but something rather than a centre line.
since the feature is asymetrical, there needs to be a tertiary for anti-rotation.
i would say fix the datums and then let's look at the profiles.
dave d.
if drawing to asme y14.5m you need to say so on the drawing or document listed by the drawing (14.5 paragraph 1.1.3).  it may seem pedantic but can make a difference and reduces confusion.
i鈥檇 perhaps make your datum d into datum b and use the flat produced by.2972 as c if you need orientation.  datum selection needs to be based on function though which i don鈥檛 fully know.
take a look in 14.5 at section 6.5.  figure 6-17 is vaguely similar to yours.
i don鈥檛 think you need the composite frames.
kenat, probably the least qualified checker you'll ever meet...
if alrayo is using ansi, it would have to 1982 or earlier version, wouldn't it?
briefly, how is this insert used, or installed in subsequent operations please?  
yes, if it really is ansi that he means then it's no more recent than 1982 but unless he has a very outdated corporate addendum to consider, there's no reason not to use the most recent standard. considering that the tolerances precede the datums then he shouldn't be working to the 1973 standard. the only ansi thing left is the 1982 standard and considering he used the suction cups as datum identifiers, i think we can safely assume he's working to the 1994 standard. the differences are so minimal anyway that we won't likely steer him in the wrong direction.
  that being said...
alrayo,
  get rid of the datums on those centerlines, change datum d to datum b and make datum c the flat on the left side of the part in the top view. redefine your datum reference frames on your profile callouts as necessary. if you use composite profile, each segment must have a datum reference, unlike composite position.
  once you have that done, repost a drawing for us and we can give you a little more help.
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thanks every one for your help, attached you can find the revised drawing attending your recommendations, additionally i have attached the drawings for components which will be matted with this component.
alrayo,
looking better.  some things to be considered:  no need for the 'cl' on centerlines.  need a class designation for the thread callout. the datum c definition is "troublesome" imho and does not go well the datum c in the fcf. a few other that the checkers should pick up on.
i assume that you have a checking group which will review your new results.