rams

Mike/Rick,
Thanks a lot.
I am interested in the Short Run SPC techniques. I would like to know how would you use the techniques on one-sided parameters (which means I can’t plot “deviation from target” as the characteristic is higher the better).
Please advise.
By the way, the characteristic is ballshear strength on semicon devices.
thanks
Rams

I assumed that having only the Cpk, you have a short-term sigma, overall average and your spec limits. Having these data, you can do the following to estimate your Ppk:
1. compute the total probability of getting out of spec measurements (assuming Normality of data) on both the LSL and USL.
2. Calculate the worst case estimate of “z-score” by…[Read more]