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  • profile Form only

    I almost hijacked another thread, sorry for that.

    Her is my question: profile .002 (no datums), disregard the -A-

    I have SR actual value .8127

    Basic .500, I get .4995


    if I understand correctly, Profile without datums uses BF. So, if the form is perfect, since the SR is .0007 over size, the best fit would put in in the middle, then the profile would be .00035 max ??
    B&S One
    PC-DMIS CAD v2014

    Romer Infinity

  • #2
    Form and form only are not the same.
    Form associates with best fit and form only is the difference between the highest and lowest points in relationship to your current alignment with no nominal involvement and no datum ref.
    I am not saying that's right or wrong, am just saying that’s how PCDMIS works.

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    • #3
      Originally posted by DungT View Post
      Form and form only are not the same.
      Form associates with best fit and form only is the difference between the highest and lowest points in relationship to your current alignment with no nominal involvement and no datum ref.
      I am not saying that's right or wrong, am just saying that’s how PCDMIS works.
      I am confused. So in regards to my values, what would be the profile without datums?

      Form only is related to the Profile right? Also BF ?
      B&S One
      PC-DMIS CAD v2014

      Romer Infinity

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      • #4
        Can’t tell without measured data (points)
        BF has nothing to do with profiling.

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        • #5
          Originally posted by DungT View Post
          Can’t tell without measured data (points)
          BF has nothing to do with profiling.
          DungT, in the previous thread initiated by Lambo, I was explained that Profile without datums acts like BF, it will move the points to BF for the profile.
          B&S One
          PC-DMIS CAD v2014

          Romer Infinity

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          • #6
            Originally posted by WolfMan View Post
            DungT, in the previous thread initiated by Lambo, I was explained that Profile without datums acts like BF, it will move the points to BF for the profile.
            True, but to further expound what DT stated is PC-DMIS Profile Form Only reporting is somewhat dependent on what algorithm is selected. In some cases the differences are small, sometimes not so small. Least Squares, Vector Least Squares and No Fit are options, each one will calculate the Profile differently.

            Which to use? Test, Test, Test. I have never seen a clear-cut rule for which to use where. It depends on what I am doing with the sample/inspection - Pass/Fail, Trouble-shooting, special request, etc.

            I can tell you it is NOT the same as Calypso.
            Last edited by ir a programmer; 05-13-2015, 10:45 AM.
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            • #7
              Originally posted by ir a programmer View Post
              True, but to further expound what DT stated is PC-DMIS Profile Form Only reporting is somewhat dependent on what algorithm is selected. In some cases the differences are small, sometimes not so small. Least Squares, Vector Least Squares and No Fit are options, each one will calculate the Profile differently.
              I am not using pcdmis, with calypso i havw least square selected. What determines which method to use? Based on my callout. Looking for more input here guys.
              B&S One
              PC-DMIS CAD v2014

              Romer Infinity

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              • #8
                If BF is how profile is used wouldnt the dev in my example be half of .0007 concidering it has perfect form and on center.
                Originally posted by ir a programmer View Post
                True, but to further expound what DT stated is PC-DMIS Profile Form Only reporting is somewhat dependent on what algorithm is selected. In some cases the differences are small, sometimes not so small. Least Squares, Vector Least Squares and No Fit are options, each one will calculate the Profile differently.

                Which to use? Test, Test, Test. I have never seen a clear-cut rule for which to use where. It depends on what I am doing with the sample/inspection - Pass/Fail, Trouble-shooting, special request, etc.

                I can tell you it is NOT the same as Calypso.
                Last edited by WolfMan; 05-13-2015, 10:51 AM.
                B&S One
                PC-DMIS CAD v2014

                Romer Infinity

                Comment


                • #9
                  Originally posted by WolfMan View Post
                  I almost hijacked another thread, sorry for that.

                  Her is my question: profile .002 (no datums), disregard the -A-

                  I have SR actual value .8127

                  Basic .500, I get .4995


                  if I understand correctly, Profile without datums uses BF. So, if the form is perfect, since the SR is .0007 over size, the best fit would put in in the middle, then the profile would be .00035 max ??
                  Originally posted by WolfMan View Post
                  If BF is how profile is used wouldnt the dev in my example ne half of .0007?
                  The Profile won't show any deviation when it is perfect, not sure I understand what you want to know. Vinni pretty much explained how PC-DMIS treats Profile in the other thread. Calypso treats it differently, that's all I know about that. A former coworker programmed with Calypso, I believe he had to use the Curve package to show Profiles correctly.
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                  • #10
                    Originally posted by WolfMan View Post
                    DungT, in the previous thread initiated by Lambo, I was explained that Profile without datums acts like BF, it will move the points to BF for the profile.
                    I don’t know who that is and what he/she/it was talking about. When you measure a circle and ask for size, the size of that circle is absolute and in perfect form in itself, and when you ask for circularity of the same circle it evaluates all of the points that were taken for that circle. Think about it, BF vs surface deviation

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                    • #11
                      I have done all
                      Kind of testing and I cannot get the result matching it to be BF. The results i get are profile max value ior Tvalue is .0007. If thats the case it does not evaluate as BF. It simply measures the form and size, deviation from the Nom Rad to the actual Radius.


                      Also, if i do form and loc, I can have form only larger than form+loc, just like i explained in the lamboo thread, it will take in consideration the size and the center location of the Rad.
                      Originally posted by ir a programmer View Post
                      True, but to further expound what DT stated is PC-DMIS Profile Form Only reporting is somewhat dependent on what algorithm is selected. In some cases the differences are small, sometimes not so small. Least Squares, Vector Least Squares and No Fit are options, each one will calculate the Profile differently.

                      Which to use? Test, Test, Test. I have never seen a clear-cut rule for which to use where. It depends on what I am doing with the sample/inspection - Pass/Fail, Trouble-shooting, special request, etc.

                      I can tell you it is NOT the same as Calypso.
                      Last edited by WolfMan; 05-13-2015, 10:57 AM.
                      B&S One
                      PC-DMIS CAD v2014

                      Romer Infinity

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                      • #12
                        Here is my post:
                        I am not very good explaining things, I can try using as example a part I am currently working on. Imaging a part that look like a big marshroom. The marshroom hat is a Spherical Radius 3" and the location to the center of the sphere comes from the bottom of the hat, 2.000. SR has a profile .002 to AB. A is the leg of the shroom, and B is the bottom flat of the hat.

                        Say the SR measures 2.950, so if you just measure a profile form Only, not to any daums, it will be .050 max t value.

                        Now, say the location of the sphere is 1.950 If you would
                        Measure form + loc, the profile to AB form and loc would be close to zero, maybe .005,.008, not .050.

                        If the location would be 2.050, the profile form and loc would be about .100. .050 radius+.050 loc

                        Here is a pic, dont mind the values, it was just an example.

                        As you can see i would get.050 form only, and .100 form and loc if the
                        Loc of the sphere is moved in the same direction to compensate for the Radius being small.
                        Last edited by WolfMan; 05-13-2015, 11:04 AM.
                        B&S One
                        PC-DMIS CAD v2014

                        Romer Infinity

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                        • #13
                          The argument was that, form could not be larger than the form and loc, bc Form
                          Only is Best Fitted.

                          My argument was that it can, if the location is shifted to the same direction which could make the form and loc to be almost zero deviarion.
                          B&S One
                          PC-DMIS CAD v2014

                          Romer Infinity

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                          • #14
                            Originally posted by WolfMan View Post
                            Here is my post:
                            I am not very good explaining things, I can try using as example a part I am currently working on. Imaging a part that look like a big marshroom. The marshroom hat is a Spherical Radius 3" and the location to the center of the sphere comes from the bottom of the hat, 2.000. SR has a profile .002 to AB. A is the leg of the shroom, and B is the bottom flat of the hat.

                            Say the SR measures 2.950, so if you just measure a profile form Only, not to any daums, it will be .050 max t value.

                            Now, say the location of the sphere is 1.950 If you would
                            Measure form + loc, the profile to AB form and loc would be close to zero, maybe .005,.008, not .050.

                            If the location would be 2.050, the profile form and loc would be about .100. .050 radius+.050 loc

                            Here is a pic, dont mind the values, it was just an example
                            This part -
                            Say the SR measures 2.950, so if you just measure a profile form Only, not to any daums, it will be .050 max t value.
                            No

                            In PC-DMIS (when dimensioned properly), Profile FORM ONLY is not affected by the measured SIZE of the feature. It only takes the MIN/MAX point range into account, which is what Vinni has already 'splained.

                            So in your above example, what is the min-to-max measured range (T values) of the points? THAT will be the Profile FORM ONLY measurement, dependent upon which algorithm was selected.
                            Last edited by ir a programmer; 05-13-2015, 09:57 PM.
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                            • #15
                              AHHH, wow, thank you so much Ira...... I though that Form only in pc-dmis represent the same thing it represents in Calypso, which is Form and Size. So, Form only represts just that FORM, or roundness in this case right?

                              So, Form + Loc, would take in consideration all 3: form, size and location? correcto?

                              let me ask you another question, if you look at the print, it shows SR.812 and profile .002 (lets not worry about -A- for now)

                              Normally, you would have SR .812 as a BASIC dim, why would you have it a basic, if FORM only, will NOT effect the size. My understanding before was, IS that having a profile .002 (with A perfect form) would allow the SR to be +/- .001, in other words it would allow the SR to be anywhere from .811/.813

                              if you say Profile .002 (form only in this case, since no datums), only effects the Min/MAX point range, then the SR can be is much as .816, with profile fr example .0012 and still be good.

                              Originally posted by ir a programmer View Post
                              This part -

                              No.

                              In PC-DMIS (when dimensioned properly), Profile FORM ONLY is not affected by the measured SIZE of the feature. It only takes the MIN/MAX point range into account, which is what Vinni has already 'splained.

                              So in your above example, what is the min-to-max measured range (T values) of the points? THAT will be the Profile FORM ONLY measurement, dependent upon which algorithm was selected.
                              Last edited by WolfMan; 05-13-2015, 11:46 AM.
                              B&S One
                              PC-DMIS CAD v2014

                              Romer Infinity

                              Comment

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