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Interpretation of the coefficient. MSA

Discussion in 'Gage R&R and MSA - Measurement Systems Analysis' started by Tommas, Dec 11, 2022.

  1. Tommas

    Tommas New Member

    Dec 10, 2022
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    I have a question about two coefficients. I know the definitions, but can someone give an example?
    What exactly is ndc?
    Is it possible to obtain all the results and then we have distinguishable measurement categories? And how does it relate to PV, for example?

    I have an example to measure 100mm +/- 1mm (tolerance)
    I measure it with a caliper with an accuracy of 0.01 mm
    So in this case I have over 200 possible results and they will be within tolerance?
  2. Miner

    Miner Moderator Staff Member

    Jul 30, 2015
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    Greater Milwaukee USA
    ndc = number of discrete categories. The Minitab blog Understanding "Number of Distinct Categories in Your Gage R&R Output has a good explanation. ndc is redundant with %SV. As %SV increases, ndc decreases. They tell you the same thing, but in a different way. I assume that PV means %Process Variation (%PV). This would be similar to % Study Variation (%SV), but with a better estimate of the process variation.

    Regarding the second question, this pertains to the measurement device's resolution. Your caliper would have an acceptable resolution, but this does not ensure that it will have an acceptable R&R.
    Bev D and Andy Nichols like this.