Failure Mode and Effect Analysis (FMEA)

Failure Mode & Effect Analysis
Tom Hannan & Kevin Kowalis
Eastern Illinois University
School of Technology
Total Quality Systems
INT 5133
What is FMEA?
“Is an analytical technique that combines
the technology and experience of people
in identifying foreseeable failure modes
of a product or process and planning for
its elimination.” ()
Before-The-Event action that makes it
easier to find flaws in the system
Is the probability of the product to perform as
expected for a certain period of time, under
the given operating conditions, and at a given
set of product performance characteristics.
Reliability Requirements
Based on the definition of the part, assembly,
or process under consideration, the reliability
of each sub-system and the factors involved
in the reliability must be found, and the
appropriate relationships for each part, class,
or module of the product must be computed.
Failure Rate
Periods of failure can conveniently be
modeled by an exponential distribution, and
the probability of survival of the product or
process may be viewed as:
Rt = e ^(-T *F) = e ^ -(T/o)
Rt = the period of operation without failure
T = time specified for operation w/o failure
F = Failure rate
O = the mean time to failure
Intent of FMEA
An Essential Part of Total Quality
Management is FMEA!
• Provides Training
• Helps communicating similar problems
• Tracks the progress of a project
• Uncovers oversights, misjudgments, and errors
• Calculate the probabilities of failures
•Determine if product or process failure effects on other aspects.
FMEA methodology is a team effort where
the responsible engineer involves who?
• Assembly
• Service
• Manufacturing
• Quality
• Supplier
• Materials
• Customer
FMEA Documentation
• Block Diagram
• Design or Process Intent
• The Customer Needs and Wants
• The FMEA Form
Class Assignment !!!!!!
Make A Simple Block Diagram
Divide up into four groups (N,S,E and W)
• Change Tire
• Flashlight
• Unicycle
• Bicycle
Stages of FMEA
• Specifying Possibilities
• Quantifying Risk
• Correcting High Risk Causes
• Re-evaluation of Risk
Specifying Possibilities
Possible Failure Modes
Root Causes
Quantifying Risk
Probability of Cause
Severity of Effect
Effectiveness of Control to Prevent
Risk Priority Number
Correcting High Risk
Prioritizing Work
Detailing Action
Assigning Action Responsibility
Check Points on Completion
Re-evaluation of Risk
Recalculation of Risk Priority Number
RPN = (S) * (O) * (D)
The Design FMEA Document
• FMEA Number
• Item
• Design Responsibility
• Prepared By
• Model Number/Year
• Key Date
• Core Team
• FMEA Date
The Design FMEA Document
• Item/Function
• Potential Failure Mode
• Potential Effect(s) of Failure
• Severity (S)
• Classification (CLASS)
• Potential Cause(s)/Mechanism(s)
of Failure
• Occurrence (O)
The Design FMEA Document
(Con. 1)
Current Design Controls
Detection (D)
Risk Priority Number (RPN)
Recommended Actions
Responsibility and Target Completion
Actions Taken
The Process FMEA Document
(Con. 2)
Process Function/Requirements
Potential Failure Mode
Potential Effect(s) of Failure
Severity (S)
Classification (CLASS)
Potential Cause(s)/Mechanism(s) of
Occurrence (O)
Current Process Controls
FMEA document’s do not fix the
identified problem
Def. of the action to fix the problem
Will not replace the basic problemsolving process.