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FMEA Guide: RPN Calculation & Examples

Last updated: 2026-08-13 · Source: MADES AI manufacturing database

This Process FMEA evaluates 3 failure modes for injection molding; the highest RPN is 252 (short shot), computed as Severity × Occurrence × Detection.

How do you calculate FMEA RPN?

RPN = Severity (S) × Occurrence (O) × Detection (D), each rated 1–10.

Failure ModeSODRPNRisk
short shot947252high
warpage756210high
sink marks465120high

What is the priority?

Focus corrective actions on the highest RPN first — typically RPN above 100 is treated as high risk.

Frequently Asked Questions

How do you calculate FMEA RPN?

RPN = Severity × Occurrence × Detection. Example: short shot 9×4×7 = 252.

What is a good FMEA RPN?

RPN above ~100 is generally considered high risk; address the highest RPNs first with corrective actions.