Failure Mode and Effect Analysis _FMEA_

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					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?

				
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posted:2/10/2012
language:English
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