Features
FMEDA – Accurate Product Failure Metrics
The letters FMEDA form an acronym for “Failure Modes Effects and Diagnostic Analysis.” The name was given by one of the authors in 1994 to describe a systematic analysis technique that had been in development since 1988 to obtain subsystem / product level failure rates, failure modes and diagnostic capability.
The FMEDA technique considers
• All components of a design,
• The functionality of each component,
• The failure modes of each component,
• The impact of each component failure mode on the product functionality,
• The ability of any automatic diagnostics to detect the failure,
• The design strength (de-rating, safety factors) and
• The operational profile (environmental stress factors).
Given a component database that is reasonably accurate [EXI06], the method can generate product level failure rate and failure mode data that is more accurate than field warranty return analysis or even typical field failure analysis.
FMEA/FMECA
A Failure Modes and Effects Analysis, FMEA, is a structured qualitative analysis of a system, subsystem, process, design or function to identify potential failure modes, their causes and their effects on (system) operation.
The concept and practice of performing a FMEA, has been around in some form since the 1960’s. The practice was first formalized in 1970s with the development of US MIL STD 1629/1629A.
In early practice its use was limited to select applications and industries where cost of failure is particularly high. The primary benefits were to qualitatively evaluate the safety of a system, determine unacceptable failure modes, identify potential design improvements, plan maintenance activities and help understand system operation in the presence of potential faults.
The Failure Modes, Effects and Criticality Analysis, FMECA, was introduced to address a primary barrier to effective use of the detailed FMEA results by the addition of a criticality metric. This allowed users of the analysis to quickly focus on the most important failure modes/effects in terms of consequence but still did not address the likelihood or probability of the failure mode which is just as important in prioritization to drive improvements based on cost / benefit comparisons.