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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.

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  • , I agree, the Annex C is very interesting.
    I just think that what they call "plane" can be a line (in 2D).
    In this case, the projection is only a dot product.

    In the excel sheet linked, I tried to do the job of creating the line and the intersection.
    If it doesnt work between french and english, you have to change "sommeprod" by"sumproduct" in the dot column formulas, and "racine" by "sqr" in X1 and X2.

    Please don't change red cells, you can change yellow ones, and of course x and y values !!!!! (here, there are calculated by a random Slight smile) and limited at 25 values (but you can extend it if you want !)
    Hope this help, remains to be done the statistics !!!!! (there's a excel example here, I don't know if it's usefull... [URL="http://www.cnomo.com/an/telechargement.php?chemin=/fichiers/2/14802/E4136115r_A_En.zip&F_fiches_ID=14802&F_fichiers_ID=18680"]www.cnomo.com/.../URL])

    Happy sunday !
  • in reply to JEFMAN
    Also, I think you are correct that when they say "plane" that line is sufficient, given that we are using the 2D XY plane, the plane that intersects it is seen as a line anyways.
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