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Capability calculations for True Position

VinniUSMC
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
  • New try with explanations (calculation of distances perp to the line and X constant)


    So... I think you were likely right from the beginning. The projection should happen along the vector of the constructed "plane" as you originally understood.

    Then, we take vpt's suggestion of finding the angle at which maximum sigma occurs to designate which angle our Cp value comes from.

    And you already calculate the Cpk1 and Cpk2 and find the minimum value there, which is our Cpk value.

    Thanks Super
Reply
  • New try with explanations (calculation of distances perp to the line and X constant)


    So... I think you were likely right from the beginning. The projection should happen along the vector of the constructed "plane" as you originally understood.

    Then, we take vpt's suggestion of finding the angle at which maximum sigma occurs to designate which angle our Cp value comes from.

    And you already calculate the Cpk1 and Cpk2 and find the minimum value there, which is our Cpk value.

    Thanks Super
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