CMM calibration

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  • CMM calibration

    Ok got a question here.
    I have a newly qualified CMM from Hexagon, an Excel in fact, and am thinking about the qualification procedure.

    I have looked at the Machine Checking Gage from Renishaw as I had one at the other place of employment and we used to use it check our machine once in a while. The MCG-1 as a matter of fact.

    I am wondering just how good this thing is. I mean it seems to me that is should show me a pretty good number inside the volume of the test arm I would be using. Should I be able to trust that gage? Seems to me that mathematically it should give me some pretty good info.
    Richard L. LaFay
    Quality Director
    Windward Inc
    Slidell, Louisiana

  • #2
    IMO you can use any known artifact to periodically check the CMM as long as all the dims are known. We made one with several tooling balls at various heights that gives us pretty good results when compared to the CMM calibration report. The main problem with the one we made is the fact that it was made from aluminum and is very temperature sensitive.
    DeWain Hodge

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    • #3
      Well my plan at this point is to use the MCG-1 as a calibration tool. As long as I test several areas of the plate I am thinking that it should be able to give me results with a good enough resolution to feel confident my machine is accurate.

      So if this gage is accurate why can't I do my own calibration every year and certify it to this gage. It is doing a volumetric measurement after all. Then every 5 years or so have a third party come out and calibrate it.

      What do you guys think?
      Richard L. LaFay
      Quality Director
      Windward Inc
      Slidell, Louisiana

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      • #4
        The deciding factor will be what your customers think. We are an aerospace shop and our customers require OEM certification to pass audits.
        GLOBAL FX 12-15-10
        3.7MR3, XP/SP2
        EXCEL 12-20-10, 9-12-9, 7-10-7

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        • #5
          Originally posted by rlafay View Post
          Well my plan at this point is to use the MCG-1 as a calibration tool. As long as I test several areas of the plate I am thinking that it should be able to give me results with a good enough resolution to feel confident my machine is accurate.

          So if this gage is accurate why can't I do my own calibration every year and certify it to this gage. It is doing a volumetric measurement after all. Then every 5 years or so have a third party come out and calibrate it.

          What do you guys think?
          That's fine except that I would not have a "third party" come in and do your calibration, have Brown and Sharpe do it. A third party can not do any controller based compensation, it is proprietary to HEXAGON and can not be accessed (legally) by a third party. Mechanicals cam be adjusted, but once you do that you may have software comps to do and then you Brown and Sharpe. By the way it's a good idea to use the MCG upon installation of the machine. I do mine before the certification of calibration by BNS and later in the year to create a history and chart the measured values.
          sigpic

          James Mannes

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          • #6
            Originally posted by jamesmannes View Post
            that's Fine Except That I Would Not Have A "third Party" Come In And Do Your Calibration, Have Brown And Sharpe Do It. A Third Party Can Not Do Any Controller Based Compensation, It Is Proprietary To Hexagon And Can Not Be Accessed (legally) By A Third Party. Mechanicals Cam Be Adjusted, But Once You Do That You May Have Software Comps To Do And Then You Brown And Sharpe. By The Way It's A Good Idea To Use The Mcg Upon Installation Of The Machine. I Do Mine Before The Certification Of Calibration By Bns And Later In The Year To Create A History And Chart The Measured Values.
            +1
            GLOBAL FX 12-15-10
            3.7MR3, XP/SP2
            EXCEL 12-20-10, 9-12-9, 7-10-7

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            • #7
              The MCG is good for repeatability.
              You need to have Hexagon come in and calibrate on an interval determined by you. They do not put a "due date" on the calibration cert or on the label.
              If you are confident that a 2-year interval is adequate, then you can use that. You should have some history to back up that decision.
              Lately, it occurs to me
              What a long, strange trip it's been.

              2017 R1 (Offline programming)

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              • #8
                Originally posted by jamesmannes View Post
                that's Fine Except That I Would Not Have A "third Party" Come In And Do Your Calibration, Have Brown And Sharpe Do It. A Third Party Can Not Do Any Controller Based Compensation, It Is Proprietary To Hexagon And Can Not Be Accessed (legally) By A Third Party. Mechanicals Cam Be Adjusted, But Once You Do That You May Have Software Comps To Do And Then You Brown And Sharpe. By The Way It's A Good Idea To Use The Mcg Upon Installation Of The Machine. I Do Mine Before The Certification Of Calibration By Bns And Later In The Year To Create A History And Chart The Measured Values.
                1++
                sigpichttp://npmichaels.com/ (My sons book)
                THANKS (CAD IS ALWAYS MASTER)
                4.3 & 4.2MR2/GLOBAL/PH10MQ/WINDOWS XP

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