how would I constrain 6 DOF of a cylindrical part with no clocking features?

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  • #16
    I've never had an issue when not constraining rotation of a cylindrical part


    • ProbFlex
      ProbFlex commented
      Editing a comment
      This is very helpful info. no one is making anyone do anything. play it Cool MetsoMetrology. I am hopping we all know this is a place we can learn, take what works for you or don't.
      Last edited by ProbFlex; 01-20-2021, 12:14 PM.

    • MetsoMetrology
      MetsoMetrology commented
      Editing a comment
      @ ProbFlex I meant no offense to anyone here, I apologize if my words seem harsh. I saved the document Neil posted for future reference in case I do experience an issue with this, I just wanted to put in my two cents. I'm hopping that's ok on here.

    • ProbFlex
      ProbFlex commented
      Editing a comment
      its all good..

  • #17
    If you're writing a simple program and all you're doing is measuring some diameters and some simple linear heights, you don't need to rotationally constrain your alignment.

    However, as you write more advanced code, its advisable to go the extra mile & constrain all 6 DOF.

    A few situations early on in my career...
    -Had an alignment..lets call it "A2". A2 DID NOT have all 6 DOF constrained (lvl, XYZ origin only). I then wanted to create some NEW alignments that use A2 as their "recall alignment".
    -A3, A4, and A5 were created... A3--> recalls A2 and rotates 60°...A4--> recalls A2 and rotates 120°...--> A5 (recalls A2 and rotates 120°).
    -Everything works on the CAD! When I ran it in real life, PC DMIS got all wigged out and kept changing my nominals and kept on changing the direction of cone angles I was reporting.

    The fix was to lock all 6DOF in A2 with a CONSTRUCED LINE for ALIGNMENT (generic line would have worked too!). The demon was very upset about A2, the situation taught me to simply always lock all 6 DOF and I never have any issues like this.

    Call me OCD, it is what it is! , but EVERY single alignment I make has a Level, Rotate, XYZ Origin (in that exact order). My template "NEWPROGRAM" has a generic PLANE, LINE, and POINT that I will use for alignment purposes (if needed).
    Last edited by DAN_M; 01-20-2021, 11:57 AM.
    SF7107(PCD), SF454(PCD), 152614(Quindos), 9159(Quindos), 7107(Quindos), B&S Manual, M&M Gear Checker


    • #18
      Neil, thanks for posting that tech sheet!
      Quick question regarding it..

      -Sheet says "It is preferable to define a theoretical plane when doing this. It is not advisable to use theoretical lines to define the orientation, since calculating the alignment becomes unstable in certain cases".
      -I have always used a CONSTRUCTED Line for "ALIGNMENT" and have never had an issue. Has the guidance regarding using theoretical planes vs the theoretical lines been amended since the release of your tech sheet?
      SF7107(PCD), SF454(PCD), 152614(Quindos), 9159(Quindos), 7107(Quindos), B&S Manual, M&M Gear Checker


      • neil.challinor
        neil.challinor commented
        Editing a comment
        Not that I know of. I think they were just making sure the method they described was 100% bullet proof. Although most people never see a problem using alignment lines, there have been very rare cases where it's caused a problem.

      • DAN_M
        DAN_M commented
        Editing a comment
        Thank you!

        I have been using CONSTRUCTED Line for "ALIGNMENT" for years with no issue, will change to a plane.

      • ProbFlex
        ProbFlex commented
        Editing a comment
        it maybe a silly question but I don't know so,
        what would be some flags to look out for ?

    • #19
      Originally posted by sealevel View Post
      Forgot you could use the Rayco magnetic rotation vector serpent. Calibrated to 90 deg increments. (shown used at -1,0,0)


      dph51 ... Am I wrong or did you mention you were retiring?
      I retired Feb 28,2020
      The day before the COVID outbreak.
      Still join in the forum, waiting for the world to calm down.


      There are no bugs, only "UNDOCUMENTED ENHANCEMENTS!"



      • sealevel
        sealevel commented
        Editing a comment
        after thinking a bit... I figured you could not ever leave here - you need to keep current with the latest 'undocumented enhancements'
        and obviously, your sig tagline had to be created by a true entomologist!

      • KIRBSTER269
        KIRBSTER269 commented
        Editing a comment
        You calm down!!!!!!!

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