ENBIS-18 in Nancy

2 – 25 September 2018; Ecoles des Mines, Nancy (France) Abstract submission: 20 December 2017 – 4 June 2018

Show the Consequences of the Traditional ISO Method for Non-Normal Ppk versus an Alternative Proposal

4 September 2018, 10:30 – 10:50


Submitted by
Rene Klerx
Didier Dumont (SKF France S.A.), Bryan Dodson (SKF Group Six Sigma), Rene Klerx (SKF Group Six Sigma)
Ppk is a widely measure for process capability, and is regarded as a measure of non-conformance. For example, a Ppk of 1.33 represents 33 parts per million not conforming to requirements given a one sided specification. When non-normal distributions are encountered, the ISO method for computing Ppk with non-normal distributions does not allow a direct transformation between Ppk and non conformance. When using popular software, the calculation method is not always understood, and in some cases, different methods are used in different modules of the same software package This presentation explores alternative methods, including the ISO method, for computing Ppk for non normal distributions along with advantages and disadvantages.

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