Systematic approaches to maintaining product quality
| Method | Purpose | Best For |
|---|---|---|
| SPC (Statistical Process Control) | Monitor process variation | Ongoing production monitoring |
| Six Sigma (DMAIC) | Reduce defects to 3.4 per million | Complex problem solving |
| PDCA (Plan-Do-Check-Act) | Continuous improvement cycles | Small process improvements |
| 8D Problem Solving | Root cause analysis | Customer complaints, major issues |
| FMEA | Risk assessment | Design and process planning |
CPK > 1.33 = Capable process. CPK > 1.67 = Excellent process. First Pass Yield (FPY) = % of units passing first time without rework.