Failure Mode & Effect Analysis Tom Hannan & Kevin Kowalis Eastern Illinois University School of Technology Total Quality Systems INT 5133 (FMEA)

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 OR

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 Tracks the progress of a project Helps communicating similar problems 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? Assembly Manufacturing Materials Quality Service Supplier Customer

FMEA Documentation Block Diagram Design or Process Intent The Customer Needs and Wants The FMEA Form

Class Assignment !!!!!! Divide up into four groups (N,S,E and W) Change Tire Flashlight Unicycle Bicycle Make A Simple Block Diagram

Stages of FMEA Quantifying Risk Correcting High Risk Causes Specifying Possibilities Re-evaluation of Risk

Specifying Possibilities n Functions n Possible Failure Modes n Root Causes n Effects n Detection/Prevention

Quantifying Risk n Probability of Cause n Severity of Effect n Effectiveness of Control to Prevent Cause n Risk Priority Number

Correcting High Risk Causes n Prioritizing Work n Detailing Action n Assigning Action Responsibility n 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 Item Design Responsibility Prepared By Model Number/Year Key Date FMEA Date Core Team FMEA Number

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) n Current Design Controls n Detection (D) n Risk Priority Number (RPN) n Recommended Actions n Responsibility and Target Completion Dates n Actions Taken

The Process FMEA Document (Con. 2) n Process Function/Requirements n Potential Failure Mode n Potential Effect(s) of Failure n Severity (S) n Classification (CLASS) n Potential Cause(s)/Mechanism(s) of Failure n Occurrence (O) n Current Process Controls

Limitations: n FMEA document’s do not fix the identified problem n Def. of the action to fix the problem n Will not replace the basic problem- solving process.

?Questions?