Abstract

(This article is Chapter 2 in D.H. Stamatis' book, Failure Mode & Effect Analysis - Item Number H0856.)A Failure Mode and Effect Analysis (FMEA) is an early warning and preventive technique that provides designers with a methodical way of satisfying the causes and effects of failures before the system, design, process or service is finalized. The FMEA prevents failures from reaching the customer.

The FMEA should begin as early in the design process as possible, and it does not end until the system, design, product, process, or service is either completed or discontinued. Until that time, the FMEA is a dynamic improvement tool and the FMEA team continues to identify and define the priority of failures using a Risk Priority Number (RPN), which is a product of the Occurrence (O), Severity (S), and Detection (D) components.The recommended steps for conducting an FMEA include: (1) Select the team and brainstorm; (2) Apply the Functional Block Diagram or Process Flow Chart; (3) Prioritize; (4) Collect data; (5) Analyze the data; (6) Derive results; (7) Confirm/Evaluate/Measure; and (8) Do it all over again.

After the completion of the FMEA, the team should take the following steps: (1) Review the FMEA; (2) Highlight the high risk areas; (3) Identify the critical, significant and major characteristics; (4) Ensure that a control plan exists and is being followed; (5) Conduct capability studies; (6) Work on processes that have a CpK less than or equal to 1.33; and (7) Work on processes that have CpK greater or equal to 1.33.