CPK

http://www.acronymfinder.com/CPK.html

Very helpful, AP#2.

Here - this may be of use: Process capability

Thanks, that verifies what I was thinking.

Calculations commonly used for Cpk assume that the process variation has a normal distribution which is symmetrical about the process mean. I your case, where you must maintain the process on one side of the mean, the process does not have a normal distribution. In this case the calculation of the process capability must be calculated from the the probability density function of your particular process. This will require someone with more expertise in statistics than me.

Could you better explain what you have as process since if you have a mean value you have values on both sides of it.

The CPK gives an indication about the eccentricity of the distribution and is a measure of the probability to have values out of tolerance interval even if the distribution is narrow with respect to the tolerance field. It does not loose its meaning even if you work on one side since the eccentricity can be such that values come out of range.

The CAM measures how narrow the distribution is with respect to the whole tolerance field. Both parameter indicate the risk to get scrap.