Quality Progress - January 2016 - 32
BACK TO BASICS
It's Fun To Work With an F-M-E-A
Prevent defects, enhance safety and increase customer satisfaction
by Kristen Johnson, assistant editor
failure mode and effects analysis
(FMEA) is a systemized group
of activities intended to recognize and evaluate the potential failure
of a product or process, identify actions
that could eliminate or reduce the likelihood of the potential failure occurring
and document the entire process.1
FMEAs help manufacturers prevent
defects, enhance safety and increase
customer satisfaction. Most are conducted in the product design or process
development stages, but conducting an
FMEA on an existing product and
process can also be beneficial.2
The main objective
An FMEA looks for all the ways a
process or product can fail. For example, a toaster could fail in several ways:
* There is a short in the power cord.
* The coils burn the bread no matter
which setting is used.
* The pop-up mechanism is too sensitive and flings toast onto the
Failures can also occur when the
user makes a mistake, and it is wise to
include both types of failures in an
FMEA. Anything that can be done to
assure the product works correctly,
regardless of how the user operates it,
will move the product closer to 100%
A product/design FMEA can
uncover problems that will result in
safety hazards, product malfunctions
or a shortened product life. They key
question to ask here is, "How can the
product fail?" A process FMEA
uncovers process problems related to
the manufacture of the product. The
key question to ask here is, "How can
process failure affect the product, pro-
cessing efficiency or safety?"4
10 steps for an effective FMEA
All product/design and process
FMEAs should follow these 10 steps:5
(See Table 1 for a sample process
1. Review the process: Gather a team
of four to six (be sure to include
people with various job responsibilities and levels of experience)
and give each member a copy of
the product's blueprint. Also, have
the team operate the product so all
members can become familiar with
the way it works.
2. Brainstorm potential failure
modes: Look at each component of
the product and identify ways it
could potentially fail.
3. List potential effects of each failure
mode: List the potential effect of each
failure next to the failure. If a failure
has more than one effect, write each
in a separate row.
4. Assign a severity rating for each
effect: Give each effect its own
severity rating (from 1 to 10, with 10
being the most severe). If the team
can't agree on a rating, hold a vote.
5. Assign an occurrence rating for
each failure mode: Collect data on
the failures of your product's competition. Using this information,
determine how likely it is for a failure to occur and assign an
appropriate rating (from 1 to 10,
with 10 being the most likely).
6. Assign a detection rating for each
failure mode and effect: List all
controls currently in place to prevent each effect of a failure from
occurring and assign a detection
rating for each item (from 1 to 10,
with 10 being a low likelihood of
7. Calculate the risk priority number
(RPN) for each effect: Multiply the
severity rating by the occurrence rating by the detection rating.
8. Prioritize the failure modes for
action: Decide which items need to
be worked on right away. For
example, if you end up with RPNs
ranging from 50 to 500, you might
want to work first on those with an
RPN of 200 or higher.
9. Take action to eliminate or reduce
the high risk failure modes:
Determine what action to take with
each high risk failure and assign a
person to implement the action.
10. Calculate the resulting RPN as the
failure modes are reduced or
eliminated: Reassemble the team
after completing the initial corrective actions and calculate a new
RPN for each failure. Then you
may decide you've taken enough
action or you want to work on
another set of failures.
1. Chrysler, Ford and General Motors, Quality
System Requirements, QS-9000, third edition
(Southfield, MI: AIAG, 1998).
2. Robin E. McDermott, Raymond J. Mikulak
and Michael R. Beauregard, The Basics of FMEA
(New York: Quality Resources, 1996).
If you would like to comment on this article, please post your remarks on the
Quality Progress Discussion Board on
www.asqnet.org, or e-mail them to firstname.lastname@example.org. QP
FMEA Process for a Toaster
RPN-risk priority number
Note: This is not a complete chart.
32 QP ** www.qualityprogress.com
Began using 10
Recommended Responsibility Action
Item and Potential Potential
Table of Contents for the Digital Edition of Quality Progress - January 2016
According to Plan
Use Your Head
Stakeholder Management 101
All About Data
Eight Simple Steps
Which Six Sigma Metric Should I Use?
Turning ‘Who’ Into ‘How’
In the Beginning
Outputs and Outcomes
That’s So Random—Or Is It?
Improving a System
Putting It All on the Table
Know the Drill
It’s Fun To Work With an F-M-E-A
Solve Problems With Open Communication
Tell Me About It
Separate the Vital Few From the Trivial Many
To DMAIC or Not to DMAIC?
Breaking It Down
1 + 1 = Zero Defects
Curve Your Enthusiasm
Make a Choice
What Is a Fault Tree Analysis?
Successful Relationship Diagrams
The Benefits of PDCA
Return on Investment
The Art of Root Cause Analysis
Why Ask Why?
Get to the Root of It
Checks and Balances
Clearing SPC Hurdles
Supplier Selection and Maintenance
Building a Quality Team
Plan Experiments to Prevent Problems
Quality Progress - January 2016