Failure Mode and Effects Analysis

What is failure mode and effects analysis (FMEA)?

Failure mode and effects analysis (FMEA) is a systematic process to assure that potential problems are identified and risks mitigated throughout product design and development.  All facets of the product and the manufacturing processes and systems to product it are considered when developing the FMEA.  In addition to managing and identifying risk, the FMEA is a tool for the facilitation of continual improvement.  Further, the FMEA serves as a structured method to capture and preserve historical information from preceding product designs and manufacturing processes.  The FMEA is intended to be a proactive, dynamic process taking place early in product design phase and prior to the purchase of equipment and tooling in the manufacturing phase.  At various stages of the product design and process development phases,  The FMEA is re-evaluated.

FMEA TYPES:

Design Failure Mode and Effects Analysis (DFMEA)– The main focus is to identify design problems that could lead to premature product failure, product safety concerns, and product manufacturability problems.  Typical inputs include customer specifications, engineering specifications, warranty claims, manufacturability data, block diagrams, previous DFMEAs, and the design verification plan and report.

Process Failure Mode and Effects Analysis (PFMEA)– The main focus is to identify process problems associated with process functions, process related failures, and manufacturing failures.  Emphasis is placed on critical process parameters and variables that require special attention to detect the identified failure modes.

RISK ASSESSMENT AND PRIORITIZATION:

The focal point of the FMEA is the resulting risk priority number (RPN) calculated for each failure mode within the design and manufacturing process.  The lowest RPN is 1 while the highest is 1000.

RPN = S x O x D

where;

S = Severity of Effect (Scale of 1 to 10; 10 most severe effect)

O = Probability of Occurrence (Scale of 1 to 10; 10 high chance of occurrence)

D = Chance of Failure Detection (Scale of 1 to 10; 10 little or no chance to detect failure)