16-11-2012, 02:13 PM
Failure Analysis Methods
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Failure Analysis Methods
•Every product or process has modes of
failure.
•An analysis of potential failures helps
designers focus on and understand the
impact of potential process or product
risks and failures.
•Several systematic methodologies have
been develop to quantify the effects and
impacts of failures.
Implementing FMEA
An FMEA can be implemented using a
hardware or functional approach, and
often due to system complexity, be
performed as a combination of the two
methods.
Hardware = loss of a component
Functional = loss of a function or feature
Failures . . .
• Defining the possible (and relevant)
failures is the key for the analysis to
produce meaningful results.
• For instance, if all we care about are
failures that cause injuries or death, then
the analysis would be much different than
one that was interested in economical
problems.
FMEA Procedure
• Review and understand product or process design; breakdown into components
(product) or steps (process).
• Brainstorm modes of failure.
• Rate the severity of each effect of failure.
• Rate the likelihood of occurrence for each failure.
• Rate the likelihood of detection for each cause of failure (i.e. the likelihood of
detecting the problem before it reaches the customer or operator).
• Compute the Risk Priority Number, RPN = Severity x Occurrence x Detection
• Implement corrective actions to minimize the occurrence of the more significant
failure modes (i.e. the highest RPN’s).
• Re-assess the product or process by another cycle of FMEA after the actions
have been completed.
• Perform regular (re)assessments of failures as needed.