Calculating Profile and Profile of Line

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  • Calculating Profile and Profile of Line

    Let's say you're results on profile points come out to lowest -.007 and highest +.016.
    The profile callout is .020 and profile of line is .010.
    I always thought that the profile would be .007 plus .016 equals .023 deviation and your line profile would be half of that.
    How do you interpret this and what would be your finding?
    I hear people determine the profile from the highest number of the profile points and multiply it by 2. So in this case it would be .016x2 equals .032 profile. But then what's the line profile?
    Need some help guys, besides professional help 0

  • #2
    To what standard? ISO or ASME?
    PC-DMIS CAD++ 2o19 R1 SP11

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    • #3
      Can you post the actual FCF showing the requirement fo the profile tolerances?

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      • #4
        ASME (last time I used it) FCF reporting in PC-DMIS, when reporting profile, treats it as form, so it adds the total difference (in your case .023).

        ISO FCF reporting doubles your greatest deviation from nominal (stock off or stock on) and reports it as A singular positive number. (Most common practice when reporting in my expirience)

        Your line profile all depends on your drawing, is it used as a refienement or does that callout stand on its own?


        gppcdmis- what if your values were -.016 to -.007? If you used the ASME calculation your profile result would be .009, would you find that value to be acceptable?

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        • #5
          If the profile control has all degrees of freedom constrained then the largest deviation x2 is the size of the zone you are using, period. If you have no datums, or only partial constraint, then things get a bit more interesting and the details of the callout are necessary to make any conclusion. The only difference between profile of surface and profile of line is whether you are measuring something that is 3D or are measuring just a 2D slice. If both symbols are referring to the same feature on your drawing they are defining two different zones and the profile of line will (should) always have a smaller tolerance because it is being used as a refinement of the 3D zone, as R2ah1ze1l mentions.
          2013MR1 SP6
          Global Frames, Tesastar-M Heads, LSP-X1M/H Probes

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          • #6
            Originally posted by gppcdmis View Post
            Let's say you're results on profile points come out to lowest -.007 and highest +.016.
            The profile callout is .020 and profile of line is .010.
            I always thought that the profile would be .007 plus .016 equals .023 deviation and your line profile would be half of that.
            How do you interpret this and what would be your finding?
            I hear people determine the profile from the highest number of the profile points and multiply it by 2. So in this case it would be .016x2 equals .032 profile. But then what's the line profile?
            Need some help guys, besides professional help 0
            as mentioned above (ejolsen)... profile to what??? the 'profile' is the defined nominal shape of feature and the tolerance is determined by the FCF. if your FCF has a constrained profile (form AND location) and tol is .020 then your 'profile' is OOT by .006. (ASME)
            if FORM ONLY, then your profile (whatever the tolerance) usually constrained to only Datum A..... could be in the next county and be acceptable.
            "The profile callout is .020 and profile of line is .010."
            means nothing without more dwg info.

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            • #7
              HTH http://www.tec-ease.com/gdt-tips-view.php?q=163
              sigpic...engineering

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              • #8
                Originally posted by R2ah1ze1l View Post
                ASME (last time I used it) FCF reporting in PC-DMIS, when reporting profile, treats it as form, so it adds the total difference (in your case .023).

                ISO FCF reporting doubles your greatest deviation from nominal (stock off or stock on) and reports it as A singular positive number. (Most common practice when reporting in my expirience)

                Your line profile all depends on your drawing, is it used as a refienement or does that callout stand on its own?


                gppcdmis- what if your values were -.016 to -.007? If you used the ASME calculation your profile result would be .009, would you find that value to be acceptable?
                That is incorrect.

                PROFILE_ISO_ASME_METHODS.jpg
                Last edited by JamesMannes; 05-12-2012, 09:17 PM.
                sigpic

                James Mannes

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                • #9
                  ASME would see and report in the FCF as 30.3 final result in the image you just posted. Atleast in 2009 edition. Since then I only use the ISO, currently running 2010MR2, I'll give it another look.

                  I'm not saying PC-Dmis wouldn't flag the value as o/tol, but your number could look perfectly legit to the tolerance and unless you expanded your results, you would not understand why a 'good' number was being flagged.

                  Helpful to me, was ALWAYS having min/max reported in the FCF so I could quickly double check to make sure the wrong calculation formula was not being used.

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                  • #10
                    Originally posted by R2ah1ze1l View Post
                    ASME would see and report in the FCF as 30.3 final result in the image you just posted. Atleast in 2009 edition. Since then I only use the ISO, currently running 2010MR2, I'll give it another look.

                    I'm not saying PC-Dmis wouldn't flag the value as o/tol, but your number could look perfectly legit to the tolerance and unless you expanded your results, you would not understand why a 'good' number was being flagged.

                    Helpful to me, was ALWAYS having min/max reported in the FCF so I could quickly double check to make sure the wrong calculation formula was not being used.
                    No, profile would be reported as .9 (the range)...

                    15.6 - 15.0 = .6
                    15.0-14.7 = .3

                    Using ISO is determined by your customer not by what you think is good for your report.
                    sigpic

                    James Mannes

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                    • #11
                      Thanks all for pitching in with your knowledge. I did not forget about you
                      Ok, the profile is on a curved surface that is assiociated with -A-(flat) and -B-(bore).
                      So the .020 is to A&B, the line is not to A & B. It's just by its self under the feature control frame.
                      I'm still reviewing your repsonses but maybe this will clear up of what I was trying to say.

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                      • #12
                        Originally posted by gppcdmis View Post
                        Thanks all for pitching in with your knowledge. I did not forget about you
                        Ok, the profile is on a curved surface that is assiociated with -A-(flat) and -B-(bore).
                        So the .020 is to A&B, the line is not to A & B. It's just by its self under the feature control frame.
                        I'm still reviewing your repsonses but maybe this will clear up of what I was trying to say.
                        If you could post a piece of the print or a cocktail napkin rendition it would be helpful. Otherwise what you are describing is a FORM AND LOCATION (on top) and FORM ONLY (on bottom). Again, it depends on what the customer has cited as the document to use; ASME or ISO. What tghey say determines what you report, Capiche
                        sigpic

                        James Mannes

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                        • #13
                          profile.jpg
                          Here is a example of what it is.

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                          • #14
                            I know this is an old thread but just in case this is still an outstanding question:
                            Based on the sketch provided:
                            Each linear slice must have meet a profile tolerance of .010 best fit within itself
                            The entire surface must meet a profile tolerance of .020 when located and oriented relative to datums A (plane) and B (cylinder)

                            So you are being given an additional .010 of tolerance to allow for location and orientation deviation and overall form deviation but the localized form is being held to a tighter tolerance.
                            2013MR1 SP6
                            Global Frames, Tesastar-M Heads, LSP-X1M/H Probes

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                            • #15
                              Thanks for the reply and your input. It makes sense

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