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% Study Variation vs % Tolorance

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  • April 9, 2013 at 12:06 pm #54361

    Daniel Galvan
    Participant

    HI Im woking on GR&R for some parts. Two operator 10 parts 3 test runs. Im want to qualify the Repetability and Reproducibility on operator and machine.
    what shoud I use to do this. I’m not worried about detecting bad parts mainly trying to get repetablity on machine and reproduciablity on operator. The % controbution is 2.62 and % study variation is 16.19 and % tolerance is 11.93 Distictive catogories 21. now if I dont add a tolorance the % controbution is low at 0.42 and study variation 6.49 Distictive catogories 21

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    April 9, 2013 at 12:23 pm #195071

    Chris Seider
    ★ 20 Years ★
    Participant

    %study variation and % contribution shouldn’t be changing when you take away the tolerance for the same gage study. Hopefully your training materials explain these terms, even briefly and you can look at the formulas.

    I’m curious why only 2 operators was selected for your gage study but this doesn’t impact my comment in the previous paragraph.

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    April 9, 2013 at 10:06 pm #195072

    Daniel Galvan
    Participant

    I’m using Mini Tab 16 for the analysis. But unfortunately my % contribution does change those are the number I get after plugging the raw data with and without a tolerance. Only two operators were selected considering their experience with metrology (measuring parts). By only having two operators impact our GR&R, is this not possible? I read it somewhere where at least two operators and 10 parts three test runs were needed to preform GR&R. I’m new to this so all the help I can get would be most appreciated. I’m going to take a class for Mini Tab to help me understand statistic and the software function for the mean time need to do my own research and read the Mini Tab instruction manual for GR&R crossed.

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    April 9, 2013 at 10:22 pm #195073

    Daniel Galvan
    Participant

    Chris were can I reference the formulas?

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    April 10, 2013 at 3:54 am #195074

    Prabhu V
    ★ 10 Years ★
    Participant

    Hi Daniel,

    In your above query, I would like to post the following:-

    a) Are you conducting an attribute gage study (since you have mentioned that “for detecting the bad parts”
    b) Or else conducting for variable study (I hope you may aware that the process and objective is entirely different for both)

    In addition, I would like to update you on the AIAG’s MSA fourth edition update, which states that the revised requirements for the MSA study (at least 10 operators with 3 parts & 3 trials)

    Please feel free to share your thoughts/comments.

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    April 10, 2013 at 7:31 am #195075

    Chris Seider
    ★ 20 Years ★
    Participant

    @mrgvl

    I don’t see how you just taking away the tolerance affecting the @study var and @ contribution. You must be somehow analyzing different data or columns?

    After using Stat>Quality Tools>Gage R&R>Gage R&R (crossed) then click Help, See Also, Methods and Formulas

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    April 10, 2013 at 7:56 am #195076

    Chris Seider
    ★ 20 Years ★
    Participant

    @prabhuvspj I suspect you got some numbers transposed? :)

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    April 10, 2013 at 9:19 pm #195077

    Prabhu V
    ★ 10 Years ★
    Participant

    Hi Chris,

    Thank you for your intimation.

    The current sequence is (at least 10 parts with 3 operators & 3 trials)

    Sorry for the inconvenience to all.

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