F.M.E.A (Failure Mode and Effect Analysis) Chapter 14 Ronette Braithwaite Tom Plotner

GOALS F.M.E.A. Reliability Block Diagrams What is it? Why is it used? How it is used. Reliability Why it is important. Block Diagrams

How are we going to accomplish the goals? Implement quality!

Survey

WHAT IS F.M.E.A?? 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 . FMEA can be explained as a group of activities intended to: Recognize and evaluate the potential failure of a product or process and its effects Identify actions that could eliminate or reduce the chance of potential failures Document the process

Cont. FMEA attempts to detect the potential product-related failure modes FMEA uses occurrence and detection probability criteria in conjunction with severity criteria to develop risk prioritization numbers for prioritization of corrective action considerations FMEA is a team effort which the engineer has to involve the assembly, manufacturing, materials, quality, service, supplier, and the next customer (internal or external)

Benefits of FMEA Improves the quality, reliability, and safety of products / services / machinery and processes Improves company image and competitiveness Increases customer satisfaction Reduces product development timing and cost / support integrated product development Documents and tracks action taken to reduce risk Reduces potential for Warranty concerns Integrates with Design for Manufacturing & Assembly techniques

Several types of F.M.E.A: design FMEA, process FMEA, equipment FMEA, maintenance FMEA, concept FMEA, service FMEA, system FMEA, environmental FMEA, and others. Design FMEA Identifies known and foreseeable failure modes Establishes priorities based on expected failures and the severity of those failures Reduces development time and the cost of manufacturing process Process FMEA Identifies potential failure modes prior to operation of the process Helps to establish priorities according to the relative impact on the internal or external customer Helps to identify potential manufacturing or assembly causes in order to establish controls for occurrence reduction and detection

Reliability Reliability defined: The probability of a product to perform as expected for a certain period of time, under the given operating conditions, and at a given set for product performance characteristics.

Why is reliability important? Reputation Customer Satisfaction Warranty Costs Repeat Business Cost Analysis Customer Requirements Competitive Advantage

What is the difference between Quality and Reliability?

TAKE A BREAK!!!! Come back in about 10-15 minutes

Block Diagram Is a simple, specialized, high-level type of flowchart. Provides a quick and uncomplicated overview of a process. Is used to design new processes or to simplify and understand existing processes. Is a starting point for process improvement.  

Simple Block Diagram

Complex Block Diagram CELL PHONE

ACTIVITY

4 Stages of FMEA Specifying Possibilities Quantifying Risk 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 a. Recalculation of Risk Priority Number

Design FMEA View Handout

Failure Mode And Effect Analysis (Design FMEA) FMEA Number______________ Page___________of__________ Item ____________ Design Responsibility___________Prepared By _______________ Mode Number/Year________Key Date__________FMEA Date (Orig.)____(Rev.)____ Core Team______________________________________________________________

List the functions of the item Item/ Function Potential Failure Mode Effect(s) of S C L A Causes(s)/ Mechanism(s) O Current Design Controls D R P N List the functions of the item Function should be written in verb-noun context Each function must be measurable Example Must hold an extra large coffee (16 oz) Heat transmission of less than xx deg

Failure modes should be described in technical terms Item/ Function Potential Failure Mode Effect(s) of S C L A Causes(s)/ Mechanism(s) O Current Design Controls D R P N Failure modes should be described in technical terms Avoid to many details Example Does not hold 16 oz. Transmits heat too quickly

Effects must be listed from the customers point of view Item/ Function Potential Failure Mode Effect(s) of S C L A Causes(s)/ Mechanism(s) O Current Design Controls D R P N Effects must be listed from the customers point of view Also state whether the failure will impact personal safety or break any product regulations Many effects may exist for each failure mode Example Insufficient quantity of coffee Must fill too often Injury to person - burn

Insufficient quantity of coffee – severity 5 Must fill too often Item/ Function Potential Failure Mode Effect(s) of S C L A Causes(s)/ Mechanism(s) O Current Design Controls D R P N View severity chart The severity applies only to the effect of the failure, not the potential failure mode If a severity of 9 or 10 is selected an action should be considered before continuing Example Insufficient quantity of coffee – severity 5 Must fill too often Injury to person (burn) – severity 10

Item/ Function Potential Failure Mode S C L A Causes(s)/ Mechanism(s) of O Current Design Controls D R P N Classify any special product characteristics for components, subsystems, or systems that may require additional process controls.

Must be listed completely and consciously Item/ Function Potential Failure Mode Effect(s) of S C L A Causes(s)/ Mechanism(s) O Current Design Controls D R P N Must be listed completely and consciously There is usually more than one cause of failure for each failure mode Causes must be identified for a failure mode, not an individual effect Example Insulation material too thick Inside cup sized incorrectly Insufficient insulation

Insulation material too thick – occurrence 5 Item/ Function Potential Failure Mode Effect(s) of S C L A Causes(s)/ Mechanism(s) O Current Design Controls D R P N View occurrence chart Occurrence is based on the chance that one of the specific causes/mechanisms will occur Each cause must be rated on the probability of occurrences as it contributes to each failure mode Example Insulation material too thick – occurrence 5 Inside cup sized incorrectly – occurrence 2 Insufficient insulation – occurrence 5

Three types of design controls Item/ Function Potential Failure Mode Effect(s) of S C L A Causes(s)/ Mechanism(s) O Current Design Controls D R P N The activities that assure the design sufficiency for the failure mode or mechanism are listed Activities may include prevention measures, design validation, and design verification Three types of design controls Prevent the cause/mechanism or failure mode effect from occurring or reduce the rate of occurrence Detect the cause/mechanism and lead to corrective actions Detect only the failure mode

The first type is the preferred method to use Item/ Function Potential Failure Mode Effect(s) of S C L A Causes(s)/ Mechanism(s) O Current Design Controls D R P N The first type is the preferred method to use Example Engineering specifications – preventive control Historical data – preventive control Functional testing – detective control

Detection is the value assigned to each of the detective controls Item/ Function Potential Failure Mode Effect(s) of S C L A Causes(s)/ Mechanism(s) O Current Design Controls D R P N View detection chart Detection is the value assigned to each of the detective controls Example Engineering specifications – no detection value Historical data – no detection value Functional testing – detection 3

Values for the RPN can range from 1 to 1000 Item/ Function Potential Failure Mode Effect(s) of S C L A Causes(s)/ Mechanism(s) O Current Design Controls D R P N RPN = (S) x (O) x (D) Values for the RPN can range from 1 to 1000 RPN is used to rank the various concerns on the document Example Insufficient quantity of coffee – severity 5, Inside cup sized incorrectly – occurrence 2, Functional testing – detection 3 S= 5 O= 2 D= 3 RPN= 30 Injury to person (burn) – severity 10, Insufficient insulation – occurrence 5, Functional testing – detection 3 S= 10 O= 5 D= 3 RPN= 150

Recommended Actions Responsibility and Target Completion Dates Action Results Taken S E V O C D T R P N Recommended actions should be focused on design, and directed toward justifying the cause of failure mode, or eliminating the failure mode Always begin with the concern with the greatest RPN and working in descending order

Recommended Actions Responsibility and Target Completion Dates Action Results Taken S E V O C D T R P N All recommended actions must have a person assigned responsibility for completion of the action There must be a completion date accompanying each recommended completion

Recalculate and record the resulting RPN Recommended Actions Responsibility and Target Completion Dates Action Results Taken S E V O C D T R P N A brief description of the actual action and its effective date should be entered Re-estimate the resulting severity, occurrence, and detection rankings after the corrective actions have been identified Recalculate and record the resulting RPN

Process FMEA

ACTIVITY

QUIZ

Occurrence numbers tell: How bad a failure is The likelihood of completing the FMEA The chance of detecting a failure The probability of a failure

FMEA stands for _________ Mode and Effects Analysis Founded Failure Function Fart

RPN development is the reason FMEAs are performed True False

Reliability is important to external and internal customers? True False

There are only two types of FMEAs – Design and Process True False

Design FMEA should always begin with: Risk priority number FMEA team Block diagram Failure rate

Is FMEA a team effort? True False

Does an organization need to implement FMEA to achieve quality? True False

Design FMEA should always start with a _________. FMEA Team FMEA evaluation Block diagram Quality function deployment

Are you comfortable in conducting your own FMEA document ? TRUE