SPC guides

Short, practical explanations for quality and process engineers — each with a free calculator to try it on your own data.

• How to calculate CpkStep-by-step worked example with 20 measurements: mean, moving range, within and overall sigma, Cp, Cpk, Pp, Ppk.
• Cpk vs PpkShort-term vs long-term capability, why they differ, and which one customers ask for.
• Nelson rules for control chartsAll 8 tests for special causes, what each pattern means, and how to use them without false alarms.
• Gage R&R: how to run and read a studyCrossed study setup, %Study Var, %Tolerance, ndc and the AIAG guidelines — with a free ANOVA calculator.