FMEA – How to Plan and Organize
November 14, 2006
Jim McLinn CRE, Fellow ASQ
What is it?
Why do an FMEA?
What is it good for?
How to do an FMEA
When to do an FMEA
1960s – NASA began a version
1974 US Military and Mil Std 1629
1978 – FDA issued Hazard Analysis
1988 - Ford issued a new document for
1990 – Chemical and Gas industry
1994 – ISO recommended Design and
1996 – FDA issued recommendation on
Source of Documents
Mil Std 1629
AIAG & SAE J1739
VDI – Z138 (German)
Other forms exist
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
FMEA Key FMEA Terms
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.
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).
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
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
Risk Priority Number which helps prioritize the findings of the FMEA
FMEA Benefits of Using FMEAs
Improves time to get reliable products to
Can reduce or prevent recalls (Sony
recalled 9.6 million batteries in 2006)
Identifies downstream maintenance
May aid in complaint investigation and
meaningful corrective actions of a process
Many others exist Slide 7
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
See Sept 2006 Quality Progress – but watch
for errors in article
FMEA Additional Considerations
2. Organization of a Team
Team Sponsor ( need not be present)
Team Leader (must be present and move team along)
• Electrical, Software or Mechanical people
• Manufacturing or Operations
• Test Engineering
• Reliability Engineering
• Field Service or repair
Coach or facilitator
FMEA Design vs. Process FMEAs
Engineer designs to fulfill customer requirements
Failure Mode = Failure to function
Cause = Design weakness
Detection = Really verification and Validation (catch
design weakness before release to
Engineering 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 When to do Design & Process FMEAs
Phase 1: Phase 2: Phase 3: Phase 4: Phase 5:
Concept Product Design & Test & Release
Development Planning Development Validation & Ramp
Initial Design Complete
Apply learning from previous projects
FMEA Some Related Tools
Function A Function B Function C
Functional Block Diagrams
Fault Tree Analysis
Many other tools exist
FMEA Functional Block Diagrams
Isa 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 FBD Example: Smoke Detector
Smoke Chamber circuit - ionizes smoke which
cases increase in voltage corresponding to signal to
be sent to control box
Indicator light - shines
when battery test button is
Vents – to smoke + depressed or when alarm is
chamber circuit activated
Wire - for
sending signal to Battery - supplies voltage
control box to entire system
Control Box - controls Test Button –
voltage to siren system Activates horn
Siren - receives voltage and
in turn produces sound.
Control wire - sends
voltage wire to siren Horn
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
FMEA FBD Example: Smoke Detector
Inputs Process Outputs
Presence of smoke Smoke enters assembly Successful capture
Light is activated
Smoke enters chamber
Smoke passes detector
Ion chamber generates
Voltage goes to control
Control box sends
voltage to Noise Maker Alarm Sounds
FMEA Fault Tree
A logical connection diagram that shows a series of related
events which lead to potential root cause(s) of a failure.
As part of a design review
When developing a new process
To analyze a failure
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 Smoke Detector Fault Tree
Fails to Detect
Partial Block Diagram
Smoke does Smoke does Smoke not
not enter the not enter detected in
assembly chamber chamber
Vent is Detector
Incorrect Mechanical Electrical Temperature Dead or low
Paint Dust Insects
installation shock overstress extreme battery
FMEA FMEAs - Failure Modes & Effects Analysis
What ? - Answered
When ? – Answered
Why - Answered
Time for a short example !!
FMEA FMEAs - Failure Modes & Effects Analysis
Sample DFMEA Form
FMEA FMEA Fault Tree to Failure Modes & Cause(s)
not enter the
Ties to FTA
Paint Dust Insects
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
FMEA FMEA Effects and Fault Detection
Next we complete the Effects and Fault Detection
FMEA 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).
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
FMEA 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
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 FMEA Occurrence
Occurrence may be ranked from 1 to 10 or 1
to 5 – as always big numbers are bad
1 more then 10 Years between fails
2 5 to 10 years OR
3 2 to 5 years 1 - Less then 0.1% The Scale Factor may be
4 1 to 2 years 2 - 0.1% to 1% changed as long as it is
5 ½ to 1year 3 – 1% to 10% applied consistently, e.g., one
minute might be a 10 and
6 Quarterly 4 – 10% to 50%
twenty four hours might be
7 Monthly 5 – More then 50% a 1.
9 Daily Rule of Thumb: A 1 should
10 Every few hours be at least the expected life
of the product.
FMEA 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 FMEA Recommended Actions
Fill out the Recommended Actions based on:
Safety Issue = Yes
RPN 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 FMEA Who & When
FMEA FMEA Audit
Key to closing out actions and making something happen
FMEA FMEA Suggestions
Take advantage of existing data
Use field experience and talk to service or
Facilitate proper brainstorming – Learn how!
Avoid jumping to solutions – A Common
Don’t get bogged down in arguments
A Recommended Action might be another
FMEA or a study
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
•Create a “Parking lot” if necessary
you have covered
the FMEA portion;
now it is time to
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
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
Come prepared to all meetings
Let the team work the issues
Watch Your Words
Use a complete sentence to express a complete idea.
Need a complete thought, so no stand alone words in a
Avoid vague words such as:
Bad, Poor & Wrong
Too, Low & No
Broken, Dead & Failed
Insufficient, unacceptable or similar words
Don’t get Confused:
Write out whole progression if
Next level impact
Top level Effects
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.
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.
Use the 30, 60 , 5 Rule
Don’t allow arguments or hidden agendas
Encourage discussion for a short time and
Come to a conclusion
Create an action to get information
Use the parking lot
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
Design Engineers job, not others
No body really cares anyway
Not cost effective
Still can’t prevent safety problems
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