Profile of a surface

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  • Profile of a surface

    I need to check the profile of part of a cylinder to DATUM A which is a milled flat on the cylinder. The tolerance is .0002 but when I check it it tells me my profile is perfect. I don't see how this is possible since I have a flatness of .0014 on the datum A surface. I scanned both surfaces, created a plane from the one surface scan and then made that my Datum A. I have done profile of the other scan and it says it is 0.000 and I have created a cylinder from the other scan and then profiled that and it also says it is perfect. How can this be if datum A is .0014 out of flat.
    Attached Files

  • #2
    Where are you getting your nominals for the scan? Are you using XactMeasure or legacy profile? If legacy, are you doing form only or form and location?

    Posting code for the scan and profile and the report could also give important clues.
    PC-DMIS 2016.0 SP8

    Jeff

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    • #3
      The datum is a perfect surface associated to the hits, so whatever its real defect, it doesn't change the result.
      In this case, A should be a tangent plane L2_constrained or minimax (depends also on the version).
      If you scan an "unknown" scan, then the theo = actual, so the profile = 0.
      Did you dimension the cylindricity of the cylinder ?
      If you scanned only a line, then you have to use line profile.
      As said Schrocknroll , post the code...
      ​​​​​​​

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      • #4
        Schrocknroll, I programmed everything off the model so my nominals are coming from the model. I have used both Xactmeasure and Legacy profile trying both form only and form and location when dimensioning the scan. They both come out as 0.0

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        • #5
          Originally posted by MJSmith View Post
          Schrocknroll, I programmed everything off the model so my nominals are coming from the model. I have used both Xactmeasure and Legacy profile trying both form only and form and location when dimensioning the scan. They both come out as 0.0
          What parameters : findnom, defined, relearn..... ?

          Comment


          • #6
            Jefman,
            Since I used the model to create the scan the theoreticles should be perfect to the model and not what I actually scan correct? It should be comparing the actual scan to the model to show what is in spec and what is out of spec correct? I have dimensioned the cylindricity and that is the other problem as it says it is .0967 which doesn't make sense. I used freeform scan for both scans to cover more surface area and get a more accurate reading.
            I am using 2018 R1 for my PCDMIS version and I am not sure how to dimension "A should be a tangent plane L2_constrained or minimax (depends also on the version)".
            I have never posted code before so how would I go about doing that?
            I feel like this is out of my current understanding so you are going to have to baby me through this.

            Thank you.

            Comment


            • #7
              Originally posted by MJSmith View Post
              Jefman,
              Since I used the model to create the scan the theoreticles should be perfect to the model and not what I actually scan correct? It should be comparing the actual scan to the model to show what is in spec and what is out of spec correct? I have dimensioned the cylindricity and that is the other problem as it says it is .0967 which doesn't make sense. I used freeform scan for both scans to cover more surface area and get a more accurate reading.
              I am using 2018 R1 for my PCDMIS version and I am not sure how to dimension "A should be a tangent plane L2_constrained or minimax (depends also on the version)".
              I have never posted code before so how would I go about doing that?
              I feel like this is out of my current understanding so you are going to have to baby me through this.

              Thank you.
              If you have the scan set to MASTER, no matter how you create it, the FIRST TIME it runs, it sets that as MASTER, as in NOMINAL. Set your scan to FIND NOMS and RELEARN.
              sigpic
              Originally posted by AndersI
              I've got one from September 2006 (bug ticket) which has finally been fixed in 2013.

              Comment


              • #8
                It looks like the cylinder scan defaulted back to master after I created my first scan and I didn't catch it. With everything switch correctly I am getting profile of .005 form and location and .0028 form only and the cylindricity is at .0023. Below is how I dimensioned the same scan using Xactmeasure and Legacy see any issues?

                FCFPROF1 =SURFACE PROFILE : SCN2
                FEATCTRLFRAME/SHOWPARAMS=YES,SHOWEXPANDED=YES
                CADGRAPH=OFF,REPORTGRAPH=OFF,TEXT=OFF,MULT=10.00,A RROWDENSITY=100,OUTPUT=BOTH,UNITS=IN
                COMPOSITE=NO,
                CUSTOMIZED DRF=NO
                STANDARDTYPE=ASME_Y14_5
                PRIMARY DIMENSION/PROFILE OF SURFACE,0.0002,<UZ>,<UTol>,A,<dat>,<dat>
                NOTE/FCFPROF1
                FEATURES/SCN2,,

                DIM PROF1= PROFILE OF SURFACE OF SET SCN2 FORMANDLOCATION UNITS=IN ,$
                GRAPH=OFF TEXT=OFF MULT=10.00 ARROWDENSITY=100 OUTPUT=BOTH
                AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
                M 0.0000 0.0002 0.0000 0.0050 0.0050 0.0048 |------->

                DIM PROF2= PROFILE OF SURFACE OF SET SCN2 FORMONLY MIN_MAX UNITS=IN ,$
                GRAPH=OFF TEXT=OFF MULT=1000.00 ARROWDENSITY=100 OUTPUT=BOTH
                AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
                M 0.0000 0.0002 0.0000 0.0028 0.0028 0.0026 <---|--->

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                • #9
                  Thanks for taking the time to help this novice out.

                  Comment


                  • #10
                    You need to show MIN/MAX on the dimensions. This is a must when you dimension profile.

                    Comment


                    • #11
                      Originally posted by Schlag View Post
                      You need to show MIN/MAX on the dimensions. This is a must when you dimension profile.
                      This is best practice but not actually a requirement. It's needed if you need to report actual numbers. If you're just looking for pass fail, PC-DMIS will calculate it correctly, it's just that the deviation will be the max to min deviation which may be misleading.
                      PC-DMIS 2016.0 SP8

                      Jeff

                      Comment


                      • Schlag
                        Schlag commented
                        Editing a comment
                        Right on...

                    • #12
                      Originally posted by MJSmith View Post
                      Jefman,
                      Since I used the model to create the scan the theoreticles should be perfect to the model and not what I actually scan correct? It should be comparing the actual scan to the model to show what is in spec and what is out of spec correct? I have dimensioned the cylindricity and that is the other problem as it says it is .0967 which doesn't make sense. I used freeform scan for both scans to cover more surface area and get a more accurate reading.
                      I am using 2018 R1 for my PCDMIS version and I am not sure how to dimension "A should be a tangent plane L2_constrained or minimax (depends also on the version)".
                      I have never posted code before so how would I go about doing that?
                      I feel like this is out of my current understanding so you are going to have to baby me through this.

                      Thank you.
                      Sorry, I was off the forum...
                      When you construct the plane which will be A, select in the constructed plane "tangente" + L2_constraint (instead of "auto" or best fit...
                      When you post some code, copy / paste the text, select it and click on the "#" just up to the window (wrap [code] tags around selected text)

                      Code:
                      FCFPROF1 =SURFACE PROFILE : SCN2
                      FEATCTRLFRAME/SHOWPARAMS=YES,SHOWEXPANDED=YES
                      CADGRAPH=OFF,REPORTGRAPH=OFF,TEXT=OFF,MULT=10.00,A RROWDENSITY=100,OUTPUT=BOTH,UNITS=IN
                      COMPOSITE=NO,
                      CUSTOMIZED DRF=NO
                      STANDARDTYPE=ASME_Y14_5
                      PRIMARY DIMENSION/PROFILE OF SURFACE,0.0002,<UZ>,<UTol>,A,<dat>,<dat>
                      NOTE/FCFPROF1
                      FEATURES/SCN2,,
                      
                      DIM PROF1= PROFILE OF SURFACE OF SET SCN2 FORMANDLOCATION UNITS=IN ,$
                      GRAPH=OFF TEXT=OFF MULT=10.00 ARROWDENSITY=100 OUTPUT=BOTH
                      AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
                      M 0.0000 0.0002 0.0000 0.0050 0.0050 0.0048 |------->
                      
                      DIM PROF2= PROFILE OF SURFACE OF SET SCN2 FORMONLY MIN_MAX UNITS=IN ,$
                      GRAPH=OFF TEXT=OFF MULT=1000.00 ARROWDENSITY=100 OUTPUT=BOTH
                      AX NOMINAL +TOL -TOL MEAS DEV OUTTOL
                      M 0.0000 0.0002 0.0000 0.0028 0.0028 0.0026 <---|--->

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