# Failure Mode and Effect Analysis _FMEA_

Document Sample

```					Failure Mode & Effect Analysis
(FMEA)
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.” ()

OR

Before-The-Event action that makes it
easier to find flaws in the system
Reliability

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 Team

FMEA methodology is a team effort where
the responsible engineer involves who?

• Service
• Assembly
• Manufacturing

• Quality                • Materials

• Customer
• Supplier
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     • Unicycle

• Flashlight      • Bicycle
Stages of FMEA
• Specifying Possibilities
• Quantifying Risk

• Correcting High Risk Causes
• Re-evaluation of Risk
Specifying Possibilities
   Functions
   Possible Failure Modes
   Root Causes
   Effects
   Detection/Prevention
Quantifying Risk

   Probability of Cause
   Severity of Effect
   Effectiveness of Control to Prevent
Cause
   Risk Priority Number
Correcting High Risk
Causes
   Prioritizing Work
   Detailing Action
   Assigning Action Responsibility
   Check Points on Completion
Re-evaluation of Risk
Recalculation of Risk Priority Number

RPN = (S) * (O) * (D)

S = SEVERITY
O = OCCURRENCE
D = DETECTION RAKING
19
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
Dates
   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
Failure
   Occurrence (O)
   Current Process Controls
Limitations:

   FMEA document’s do not fix the
identified problem
   Def. of the action to fix the problem
   Will not replace the basic problem-
solving process.
?Questions?

```
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
 views: 25 posted: 2/10/2012 language: English pages: 20