algo-mfg-fmea

# FMEA (Failure Mode and Effects Analysis) ## Overview FMEA systematically identifies potential failure modes, their effects, causes, and current controls. Each failure is scored on Severity (S), Occurrence (O), and Detection (D) on 1-10 scales. RPN = S × O × D prioritizes which risks to address first. AIAG-VDA FMEA (2019) replaces RPN with Action Priority (AP) matrix. ## When to Use **Trigger conditions:** - Designing new products/processes and identifying risks proactively - Systematically evaluating existing failure modes for prioritization - Meeting automotive (IATF 16949) or medical device (ISO 13485) quality requirements **When NOT to use:** - For root cause analysis of a known problem (use fishbone/5-why) - For statistical analysis of defect data (use SPC or Pareto) ## Algorithm ``` IRON LAW: Severity Can NEVER Be Reduced by Design Changes Severity is determined by the EFFECT on the customer. A brake failure is always severity 10, regardless of how unlikely or detectable it is. FMEA reduces risk by: lowering Occurrence (better design/process) or improving Detection (better testing/inspection). NEVER inflate Detection scores to lower RPN artificially. ``` ### Phase 1: Input Validation Define scope: Design FMEA (DFMEA) or Process FMEA (PFMEA). Assemble cross-functional team. Prepare: process flow diagram or system block diagram. **Gate:** Scope defined, team assembled, reference diagrams available. ### Phase 2: Core Algorithm 1. List all potential failure modes ...