FMEA

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November 14, 2006

Minnesota ASQ

Jim McLinn CRE, Fellow ASQ

FMEA – How to Plan and Organize

FMEA

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Naked FMEAs

What is it?

Why do an FMEA?

What is it good for?

How to do an FMEA

When to do an FMEA

FMEA

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History

1960s – NASA began a version 1974 US Military and Mil Std 1629 1978 – FDA issued Hazard Analysis 1988 - Ford issued a new document for

suppliers 1990 – Chemical and Gas industry 1994 – ISO recommended Design and

Process FMEAs 1996 – FDA issued recommendation on

FMEAs

FMEA

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Source of Documents

Mil Std 1629 IEC 812 ARP 5580 RADC TR83-72 AIAG & SAE J1739 VDI – Z138 (German) British Standards Other forms exist

FMEA

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The FMEA Agenda

FMEAs can be done for a product design or a wide variety of business processes.

The intent is to improve the design or process by finding potential problems

and avoiding them.

FMEA

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Key FMEA Terms

Failure Mode The manner in which a part or assembly could potentially fail to meet it’s

requirements or fail to function. It is what you may reject the part for.

Effects The potential non-conformance stated in the terms of the next assembly or at the

system (top level) performance (usually from the customer’s perspective).

Causes The potential reason(s) behind a failure mode, usually stated as an indication of a

specific design or process weakness. This starts the chain of events leading to the Effect.

Analysis By using an FMEA model, you will anticipate failure modes,determine and

assess risk to the customer, product or process, and then act to neutralize the risk or reduce it to acceptable levels

RPN Risk Priority Number which helps prioritize the findings of the FMEA

FMEA

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Benefits of Using FMEAs

Improves time to get reliable products to market

Can reduce or prevent recalls (Sony recalled 9.6 million batteries in 2006)

Identifies downstream maintenance considerations early

May aid in complaint investigation and meaningful corrective actions of a process

Many others exist

FMEA

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Team Formation Challenges

1. Team Formation

All people must participate with no dominant stars

Should be small: 5 - 8 People are best Multi-Disciplined should be present Product/Process Knowledge is key Responsibility Level - Must have the

authority to get things done Customer Oriented – Driven to prevent

problems for customers See Sept 2006 Quality Progress – but watch

for errors in article

FMEA

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Additional Considerations2. Organization of a Team

Team Sponsor ( need not be present) Team Leader (must be present and move team along) Support Groups Design Engineering

• Electrical, Software or Mechanical people

• Manufacturing or Operations• Test Engineering• Reliability Engineering• Field Service or repair

Scribe Coach or facilitator

FMEA

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Design vs. Process FMEAs

Design FMEAEngineer designs to fulfill customer requirements

Failure Mode = Failure to functionCause = Design weakness

Detection = Really verification and Validation (catch design weakness before release to manufacturing)

Process FMEAEngineering design process to meet specification

Failure Mode = Reject (Out of specification)Cause = Process weakness

Detection = Controls in place on process to prevent rejects from reaching the customer.

FMEA

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Project Phases…

Phase 1:Concept

Development

Phase 2:ProductPlanning

Phase 3:Design &

Development

Phase 5:Release& Ramp

Phase 4:Test &

Validation

Apply learning from previous projects

Initial Design Complete

When to do Design & Process FMEAs

Design FMEA

Process FMEA

FMEA

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Functional Block Diagrams Fault Tree Analysis Flow Diagrams Process Mapping Many other tools exist

Some Related Tools

Function A Function B Function C

FMEA

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Functional Block Diagrams

Is a tool to describe the operation of a piece of equipment or process.

Allows all team members to develop a shared understanding of the operation or process to be improved.

Develops a concise starting point and ending point for analysis of the system.

FMEA

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Smoke Chamber circuit - ionizes smoke which cases increase in voltage corresponding to signal to be sent to control box

How the Smoke Detector works: Smoke enters the vent and goes into the smoke chamber 2) The chamber detects the presence of certain traces of smoke 3) If enough smoke is present chamber sends signal to control box 4) control box then draws most of voltage in entire system to siren 5)Voltage from battery in turn activates obnoxious siren sound

FBD Example: Smoke Detector

Indicator light - shines when battery test button is depressed or when alarm is activated

Battery - supplies voltage to entire system

Siren - receives voltage and in turn produces sound.

Horn

Control wire - sends voltage wire to siren

Control Box - controls voltage to siren system units

Wire - for sending signal to control box

Vents – to smoke chamber circuit

Test Button – Activates horn

+

FMEA

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Inputs Process Outputs

Control box sends voltage to Noise Maker

Smoke enters chamber

Smoke passes detector

Loud Noise

FBD Example: Smoke Detector

Voltage goes to control box

Ion chamber generates voltage

Light is activated

Alarm Sounds

Presence of smoke Smoke enters assembly Successful capture

FMEA

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Fault Tree

What ? A logical connection diagram that shows a series of related

events which lead to potential root cause(s) of a failure. When ?

As part of a design review When developing a new process To analyze a failure

Why? To minimize high risk or weak links in a design To reduce/eliminate process weaknesses To understand root cause(s) of a failure in a multiple

connection or interaction environment.

FMEA

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Smoke Detector Fault Tree

Smoke doesnot enterchamber

Smoke doesnot enter the

assembly

Vent isblocked

Paint Dust InsectsIncorrect

installation

Dust

Smoke Detector Fails to Detect

Smoke

Smoke notdetected inchamber

Detectorbroken

Mechanicalshock

Electricaloverstress

Temperatureextreme

Dead or lowbattery

Partial Block Diagram

FMEA

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FMEAs - Failure Modes & Effects Analysis

What ? - Answered

When ? – Answered

Why - Answered

Time for a short example !!

FMEA

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FMEAs - Failure Modes & Effects Analysis

Sample DFMEA Form

FMEA

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Smoke doesnot enter the

assembly

Vent isblocked

Paint Dust InsectsIncorrect

installation

FMEA Fault Tree to Failure Modes & Cause(s)

Each of the lowest level entries in the Fault Tree are potential Causes for the Failure Modes

There should be at least one Cause for each Failure Mode branch

MultipleLevel OptionTies to FTALevels

FMEA

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FMEA Effects and Fault Detection

Next we complete the Effects and Fault Detection columns together.

FMEA

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FMEA Severity

Next complete the Severity column. Severity may ranked from 1 to 10 or as a 1 to

5 for simple systems (Big number most severe). OR

1- Failure Mode is of such a minor nature that special equipment or knowledge is required to identify. This is NO IMPACT to System.

2 - Failure Mode will result in a slight system impact and / or a slight deterioration of system performance.

3 - Failure Mode will result in noticeable system deterioration and may be described as a “limp along”.

4 - Failure Mode will result in a non-function of a critical system item.

5 - Failure Mode will result in a safety problem or non-compliance with government regulation.

FMEA

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FMEA Detection or Verification Detectability can be ranked from 1 to 10 or 1

to 5(Big number is least likely to be identified in Product Development).

OR

1 - Very high probability that the Failure Mode will be identified. Verification or Validation (V&V) or other activity will almost certainly identify the existence of the (potential) defect.

2 - High probability that the Failure Mode will be identified. V&V or other activities have a good chance of identifying the existence of the defect.

3 - Moderate probability that the Failure Mode will be identified. V&V or other activities are moderately likely to identify the existence of the defect.

4 - Low probability that the Failure Mode will be identified. V&V or other activities are not likely to identify the defect.

5 - Very low probability that the Failure Mode will be identified. V&V or other activities will not or cannot identify the existence of a defect.

FMEA

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FMEA Occurrence

Occurrence may be ranked from 1 to 10 or 1 to 5 – as always big numbers are badRanking:1 more then 10 Years between fails

2 5 to 10 years OR

3 2 to 5 years 1 - Less then 0.1%

4 1 to 2 years 2 - 0.1% to 1%

5 ½ to 1year 3 – 1% to 10%

6 Quarterly 4 – 10% to 50%

7 Monthly 5 – More then 50%

8 Weekly

9 Daily

10 Every few hours

The Scale Factor may be changed as long as it is applied consistently, e.g., one minute might be a 10 and twenty four hours might be a 1.

Rule of Thumb: A 1 should be at least the expected life of the product.

FMEA

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FMEA Risk Priority Number

Calculate the Risk Priority and find top 20%

RPN is the product of S*D*O.

Top 20% are big impact items to improve

Also include all safety items to prevent or mitigate

Look at any remaining top Severity items

FMEA

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Fill out the Recommended Actions based on:Safety Issue = YesRPN ranking (start with the top 20%)When should we do more than 20%?

Easy fixes that require minimal resources Others that the team feels are important

FMEA Recommended Actions

FMEA

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FMEA Who & When

FMEA

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FMEA Audit

Key to closing out actions and making something happen

FMEA

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FMEA Suggestions

Take advantage of existing data Use field experience and talk to service or

repair people Facilitate proper brainstorming – Learn how! Avoid jumping to solutions – A Common

Engineering Mistake Don’t get bogged down in arguments A Recommended Action might be another

FMEA or a study

FMEA

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Keep Metrics of the FMEA – For Example look at Statistics:

• Total number of entries

• Total number of Safety items

• Make a RPN Histogram

• Identify Entries requiring work

• Do man-load time estimates of meetings

•Create a “Parking lot” if necessary

FMEA

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Congratulations, you have covered the FMEA portion; now it is time to address the MANAGEMENT of the FMEA

FMEA

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Ways to Improve FMEAs

•Make sure there is management buy-in

•Spend lots of time with group in FMEA

•Plan, Plan, Plan

•Come with forms filled out

•Identify purpose, limits, goals and customers.

•Define all terms up front.

•Set aside enough time.

•Do the follow up

FMEA

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Train the Team

Be sure to include training time for team Have drawings and aides at hand. Run team meetings for 2 to 3 hours and

then stop. Come prepared to all meetings Let the team work the issues

FMEA

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Watch Your Words

Use a complete sentence to express a complete idea. Need a complete thought, so no stand alone words in a

section Avoid vague words such as:

Bad, Poor & Wrong Too, Low & No Broken, Dead & Failed Insufficient, unacceptable or similar words

FMEA

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Don’t get Confused:Write out whole progression if necessary

Root Cause

Mechanism

Defect

Growth

Failure

Failure Mode

Next level impact

Top level Effects

FMEA

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Other types of FMEAs

Process FMEAs are common Maintenance or service FMEAs are done Focus on single item such as Hazards FMEA covering something new Functional level FMEAs

Try each one, but remember they might have different formats or requirements.

FMEA

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Get the relationships Correct

Severity is the numerical equivalent of Effects Occurrence speaks to likelihood of Cause Verification talks about adequacy of V&V tests. For a process FMEA, Detection talks about adequacy

of Current Controls.

NEVER, NEVER, NEVER depend upon the customer to find or detect problems.

FMEA

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Team Dynamics

Use the 30, 60 , 5 Rule Don’t allow arguments or hidden agendas

Encourage discussion for a short time and then either: Come to a conclusion Create an action to get information Use the parking lot

FMEA

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FMEA Myths

It takes a lot of time Just a pile of paperwork in the end Corrective actions cost too much Difficult to implement FMEAs because of

roadblocks Design Engineers job, not others No body really cares anyway Not cost effective Still can’t prevent safety problems

FMEA

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In Conclusion

Come Prepared Keep it simple Keep it focused Keep it short Keep it moving Follow up on action items Practice your team leader skills Collect Lessons Learned