Prozeßfähigkeit f (QS-Begriff)
process capability
[Siemens]

CPK is a unit used for reporting process capability and stays the same in English and in German (couldn't figure out what it stands for, though).

Process capability and process performance index studies are to assess a process relative to specification criteria. Quantification of this measurement is often reported using units Cp, Cpk, Pp, and/or Ppk. Statisticians often challenge how well commonly used capability indices do this; however, the fact remains customers often request these indices when communicating with their suppliers. A customer might set process capability/performance targets then ask their suppliers for their level of conformance to these targets.
The equations for process capability/performance indices are basically very simple; however, they are very sensitive to the input value for standard deviation (s ). Unfortunately there can be differences of opinion on how to determine standard deviation for a given situation. Some organizations consider Cp and Cpk are a measure of "short-term" capability, while Pp and Ppk are a measure of long-term capability; however, all organizations don't agree with this procedure. Motorola considers Cp and Cpk to be long-term. An internal or external process is considered to be Six Sigma if Cp is equal to or greater than 2.0 and Cpk is equal to or greater than 1.5. A process with these indices has a calculated defect rate of 3.4 parts per million. In addition, it should be noted that the traditional equations are for normally distributed data. Computer programs can often address situations where data are not from a normal distribution.
www.smartersolutions.com/html/process_capability.htm

Customers of semiconductor manufacturers often require that the process capability (Cpk) of critical processes be reported on a periodic basis. However, practical problems can undermine the usefulness of the Cpk. Manufacturers may have different lists of critical parameters possibly with different specification limits, making comparison between manufacturers difficult. The formulas for Cpk's and the confidence intervals may be used differently (e.g., using the average of lot (sub- group) Cpk values instead of using the individual observations from the whole sample), causing differences which may not be apparent to the customers. The sampling plans and metrology capabilities for data collection are usually intended for statistical process control, and may not be suitable for the calculation of Cpk values. Many of these problems can be addressed by standardization. It is also useful to compute variance components, and to track them as well as the Cpk over time, with goals for improvement and stability.
www.itl.nist.gov/div898/conf/jrc/abstracts/w4g.html

· Kritische Prozessfähigkeit (CPK)
www.aac-gmbh.com/Produkte/Pruefen-PiezoWin.htm

SI Compact
... der inspizierten Lose und wertet diese aus. Sie errechnet CPK-Werte (kritische Prozessfähigkeit) aller inspizierten Prüflinge oder nur aller als "gut ...
www.baslerweb.com/de/products/si/compact02.html

HTH