PPAP Element 11 Initial Process Studies: What Ppk Value Passes and Why Reviewers Reject the Number Before They Read It
Element 11 is where the statistical work of a PPAP package either holds up or collapses. A reviewer's-seat walkthrough of Initial Process Studies under AIAG PPAP 4th Edition: why initial studies report Ppk and not Cpk, the three-tier acceptance criteria at 1.33 and 1.67, the two prerequisites a reviewer verifies before trusting your index, the significant production run sample rules, the non-normal and one-sided characteristic trap that voids a clean-looking number, five kickback patterns, and a pre-submission QA pass you can run in fifteen minutes.
Gauge R&R Acceptance Criteria: %GRR, NDC, and What AIAG MSA Requires
A Gauge R&R study passes when %GRR is under 10% and NDC is at least 5. Between 10% and 30% is conditional. This guide covers the AIAG MSA thresholds, what %GRR and NDC mean, which values trigger rejection, and what to do when a measurement system does not pass.