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Capability calculations for True Position

Has anyone come across this as a means of calculating Cpk of a true position?

http://documentation.statsoft.com/ST...tionCapability

I think it should be possible, but I'm not sure if this is the answer or not. I was thinking about how something along the lines of the complex plane (or vectors/trig) could be used to identify grouping of a positional tolerance based on its quadrant within a unit circle, and then could be used to calculate Cpk. It's not unheard of. The normal distribution of a multivariate system is calculable, so why wouldn't a statistic that is related to the normal distribution in 1 variable work for higher dimensions?

I'm thinking that there must be a way to calculate the variance of position based on the the quadrant it falls in. Whether it's a trigonometric function, or a complex function.

Anyone have any input as I dive into this blackhole?

Curiosity killed the cat, hopefully I'm not a cat.

Parents
  • I suppose you are on point with this:

    By means of the calculated standard deviation and the distance between the two points of intersection, which
    makes up the tolerance zone in the relevant direction, Cp can be calculated for the orientation given by the plane in
    question.

    Page 27.


    I think it's OK.
    I'm just wondering if CP="local tol"/3sigma or ="local tol"/6 sigma...
Reply
  • I suppose you are on point with this:

    By means of the calculated standard deviation and the distance between the two points of intersection, which
    makes up the tolerance zone in the relevant direction, Cp can be calculated for the orientation given by the plane in
    question.

    Page 27.


    I think it's OK.
    I'm just wondering if CP="local tol"/3sigma or ="local tol"/6 sigma...
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