Process Capability Cpk and Ppk — Don't Confuse the Two Indices
Abstract : During an audit, Ppk is asked for, but the report only contains Cpk; Cpk is 1.67, yet frequent out of spec co…
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· 6/22/2026
Cpk Only 0.82, Customer Issues an Ultimatum? — A Case Study of Process Capability Improvement in an Automotive Parts Company
1. Introduction: An Audit Report Reveals the True Picture An automotive parts company specializes in spline shafts, with…
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· 8/17/2026
Advancing QE Skills (11) | Capability Analysis for Non-Normal Data: Transformation, Box-Cox, and Non-Parametric Methods
A mechanical processing company submitted an initial process capability report to a client, focusing on the roundness of…
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· 9/21/2026
Advancing QE Capabilities (15) | When Capability is Insufficient, Should You Change the Process or the Specification: A Dialogue Between Capability and Specification
1. A Meeting Held Three Times Without a Conclusion A car parts company's bracket hole size, after six months of mass pro…
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· 9/25/2026
What's the Difference Between Cpk and Ppk? —— The Same Process, Cpk 1.35 and Ppk 0.93, What Does the 0.42 Difference Indicate?
1. Reviewing the Scene: Two Conflicting Numbers A process capability review at a precision stamping factory. On the proc…
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· 10/17/2026