Profile of a surface

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  • Profile of a surface

    Good Morning Everyone,
    I had a situation with our Engineering Group and VP. A callout on a print has "profile of a surface to datums AB&C, with a tol of 1.5mm". The part is a rail about 550mm in length. The callout is refering to the edge surface. Basically the straightness of the part. Ok, this is the question.
    If I use the profile option in pc dmis, then I have to take several points, create a line and profile dimension the line. The software will only allow a positive value. That would be 1.5.
    However the group pulled the GD&T examples out of their files and according to that, then I should dimension all the points taken and tolerance them as
    ±.75mm.
    What is the correct way of doing this????????

    Thanks in Advance,
    A.Gore
    sigpicA.Gore

  • #2
    use form and location - make sure you enter the nominals or they are taken from clicking the cad model

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    • #3
      Either way is correct. Using the profile of a surface will (should) give the same in/out of tolerance, but by measuring individual points and dimensioning the individual points, you get instant results of IF it is out and if so, where. You simply use DIM LOCATION and use XYZT for the report axis. If these are edge points, you can also use a single surface sample hit (you should, anyway) and you can add the S axis for the surface deviation.
      sigpic
      Originally posted by AndersI
      I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.

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      • #4
        If you are dimensioning the profile to datums, make sure you have "form and location" selected, then you can dimension it +/- .75
        PC-DMIS 2016.0 SP8

        Jeff

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        • #5
          I like to report the points individal
          if you use form and and it measures .90 = -.20 +.70
          Engineers think it is bad - then you may need to do min/max
          each engineer is different
          DR Watson shut me down again !!!! :mad: Smoke break:eek:

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          • #6
            be sure to check the print to determine if your looking at a bilateral or unilateral profile tolerance as indicated by dashed lines around the surface to be checked. if it is a unilateral profile tolerance you may have to dimension it
            +1.5mm or -1.5mm depending on the callout.
            sigpic
            Southern Man don't need him around anyhow!

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            • #7
              Tolerancing

              The print does not identify the uni or bilateral tolerances. It only has the control frame pointing to the edge. Under that, it has the sets of points that are to be dimensioned. Attached is the trihedron and the control frame. The strip length is in the Y, the measurable is the X.

              Thanks for the Help,
              A.Gore
              Last edited by ag162; 07-10-2006, 09:08 PM.
              sigpicA.Gore

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              • #8
                The default for Surface profile is equal bilateral.

                I report each point individualy, and give the "total profile" also.
                kb
                RFS Means Really Fussy Stuff

                When all you have is a hammer - everything looks like a nail....
                sigpic

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                • #9
                  profile tolerance

                  Originally posted by ag162
                  The print does not identify the uni or bilateral tolerances. It only has the control frame pointing to the edge. Under that, it has the sets of points that are to be dimensioned. Attached is the trihedron and the control frame. The strip length is in the Y, the measurable is the X.

                  Thanks for the Help,
                  A.Gore
                  the profile callout for unilateral or bilateral is not in the feature control frame. there should be dashed lines at the end of the arrow leader to indicate both sides of the surface to be checked (bilateral) or there may be dashed lines offset to one side of the surface to be checked (unilateral) to detemine how you apply the tolerance. if no dashed lines are apparent- bilateral tolerancing is "implied". i also report points as others have mentioned.
                  sigpic
                  Southern Man don't need him around anyhow!

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                  • #10
                    The only problem with doing it "as needed", is that I usually don't find that out till somewhere in the middle of the program.
                    James Temmen

                    There is no job so simple that it can't be done wrong.

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                    • #11
                      of coarse
                      Oh by the way
                      here is an updated print
                      Am I too late ?
                      DR Watson shut me down again !!!! :mad: Smoke break:eek:

                      Comment


                      • #12
                        Grrrrrrrrrrr

                        Originally posted by J Temmen
                        The only problem with doing it "as needed", is that I usually don't find that out till somewhere in the middle of the program.
                        How timely, it just happened to me today, but it went like this.

                        Engineer: Jamie, I decided we'd be better off if the features on this pan face were dimensioned off of A|B|E rather than A|B|C.

                        Me: I already wrote and dimensioned the program using the original datum structure, I even suggested the revised way from DAY ONE, but you didn't want to do it!!

                        Engineer: We (head engineer and him) mulled it over for a while (2 weeks!) and decided we'd get better tolerancing from this method. (like I told them two weeks ago?)

                        I wish it was FRIDAY!!!
                        CMM Programmer
                        Jackson Michigan
                        Mistral 7.7.5
                        4.3MR2

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                        • #13
                          Originally posted by george frick
                          the profile callout for unilateral or bilateral is not in the feature control frame.....
                          Ahhh....but it will be

                          Kev
                          RFS Means Really Fussy Stuff

                          When all you have is a hammer - everything looks like a nail....
                          sigpic

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                          • #14
                            This is one of the good ones. It does usally depend on the engineers. I do it as points, And then I report only the worst case, and double it and put that on the results. I then submit the CMM Report with it. If there is any questions I revert to the Report. Some will want the +/- I will give it only when requested. And that is not to often. Right or wrong that how I do it. And have never been taken to the floor for it.
                            sigpicSummer Time. Gotta Love it!

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                            • #15
                              That is exactly how I report it also.
                              kb
                              RFS Means Really Fussy Stuff

                              When all you have is a hammer - everything looks like a nail....
                              sigpic

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