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Quick question About ISO.....

If a Blueprint calls for ASME Y14.5 wouldn't this be the standard rules apply. How would I know if and when to apply ISO? I have yet to see anything on a blueprint stating this. The reason I bring this up is for the good old Profile callout. Before I make an argument, I want to cover all my resources. Customer already claims in an email that PC-DMIS is not capable of doing this. I and everyone on here already that's horse_S_H_I_T. But its Friday and I'm ready to P_I_S_S someone off
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  • Yes, I agree that the standard does not specifically tell you how to report the bi-lateral profile deviation,
    and , what you wrote does make sense, from a certain point of view. As Vinni points out your understanding is also not specified as THE way to report it.
    Consider this:
    Does the standard specifically tell us how to report position deviation either? Does it say to calculate the radial deviation and multiply it by two?
    I just spent ~30 minutes using search terms like multiply, hyp, calculate, circular, radial, two, diametral and did a visual scan of the true position sections of the 94 standard, and did not find anything that tells us how to calculate and report the positional deviation of a hole location. (You might be able to argue that the standard implies how it should be reported.)
    Yet everyone knows that we do it by : =(SQRT(A^2+B^2))*2 (to state it as an excel formula).
    Why do we report it that way? Because we know that we are dealing with a cylindrical tolerance zone and that if we dont double it, we would be reporting it as if it were a radial tolerance zone.
    (Note, I was first exposed to true position at a military manufacturer 35 years ago who actually used Radial true position on their prints. I haven't seen anyone else use it since then).
    Likewise, it makes sense that with a bi-lateral tolerance zone whose width is centered on a plane or line, you would relate the greatest deviation (which is either on one side or the other) back to its width tolerance zone by doubling it.
    I agree with Don day of Tec-Ease. Doubling it only makes sense.


    I, personally, would have a hard time arguing that the myriad of times the standard talks about diametrical/cylindrical tolerance zones, versus the zero times it refers to radial tolerance zones (I didn't do a document search of 2009, but I don't recall it ever being mentioned), implies that one would ever not report the diametric deviation. The shape of the tolerance zone, IMHO, rather does dictate that it must be reported diametrically (otherwise you aren't reporting to the cylindrical tolerance zone...)

    It doesn't make sense, to me, to attempt to equate position and profile. They are not the same, or even similar. For instance, one cannot have a unequal distributed TP. So, if we disregard that argument, we're left with reporting profile in a way that is the same regardless of whether it's equally, or unequally, distributed. One method works for all profiles, the other only works for equally distributed. Coincidentally, this also better coincides with the method of defining an unequal tolerance zone " overall size (u) amount on + material side". If our concern is the overall size of the feature within the tolerance zone, then forcing the + and - tolerance to be equally split does us no good. Of course, reporting only the difference between max and min also does us no good. Slight smile Neither value alone tells us what we need to know. Reporting min and max is the only way to really comply.

    In the latest revision (which I've yet to see, so I don't know how it's implemented) it seems that this question is being answered for us. That still begs the question, but how do we report profile of anything other than equally distributed?
  • I really like profile. I just don't like seeing profile reported as a single number. Used properly, it's a handy tool, and it's extremely powerful.
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