Good FMEAs, Bad FMEAs - What's the Difference?
"Good judgment comes
from experience and experience comes from poor judgment."
– Will Rogers
What’s your reason for doing a Failure Modes and Effects
Analysis (FMEA)? Do you want to reduce the high cost of
warranty and stem the loss of customers due to product defects?
Do you want to prevent safety problems from causing harm
or resulting in expensive lawsuits? Maybe you wish to design in
safety and reliability to products or to manufacturing processes?
Possibly you are mandated by your customer to perform FMEAs. There are countless reasons
to use FMEAs in product development and operations. Whatever
your reason, you believe FMEAs have the potential to achieve
your goals … and you are right.
However, there’s a caveat, and it’s a big one. Not everyone
gets uniformly great results from FMEAs. They have to be
done properly, with the right preparation, the right team
composition and the right procedure. In addition, they have
to be done in such a way that they don’t consume excessive
time and money. Done correctly, FMEAs will save money, speed
up product development, increase safety, and achieve high
reliability in products and processes. However, done improperly,
they can waste time and not add value.
Why is there so much variation in the application of
a tool that has been around for many decades? What can be
done to help achieve more uniformly successful results?
In other words, what are the quality characteristics of
an effective FMEA, and how can these be evaluated and achieved?
This article will answer these questions and more in the
following sections:
The Hot Topics article in next month’s HotWire
will describe the audit procedure of an actual FMEA and
allow readers to practice auditing an FMEA.
Failure Mode and Effects Analysis is a method designed
to:
- Identify and fully understand potential failure
modes and their causes, and the effects of failure on
the system or end users, for a given product or process.
- Assess the risk associated with the identified failure
modes, effects and causes, and prioritize issues for
corrective action.
- Identify and carry out corrective actions to address
the most serious concerns.
The primary objective of an FMEA is to improve the design.
For System FMEAs, the objective is to improve the design
of the system. For Design FMEAs, the objective is to improve
the design of the subsystem or component. For Process FMEAs,
the objective is to improve the design of the manufacturing
process.
There are many other objectives for doing FMEAs, such
as:
- Identify and prevent safety hazards
- Minimize loss of product performance or performance
degradation
- Improve test and verification plans (in the case
of System or Design FMEAs)
- Improve Process Control Plans (in the case of Process
FMEAs)
- Consider changes to the product design or manufacturing
process
- Identify significant product or process characteristics
- Develop Preventive Maintenance plans for in-service
machinery and equipment
- Develop online diagnostic techniques
Based on evaluating thousands of FMEAs from hundreds
of companies, certain mistakes are repeated over and over.
By learning from these mistakes, we can set quality objectives
that will assure high quality FMEAs. Directly below are
the ten FMEA quality objectives:
- DESIGN IMPROVEMENTS The FMEA
drives product design or process improvements as the
primary objective.
- HIGH-RISK FAILURE MODES The
FMEA addresses all high-risk failure modes with effective
and executable action plans.
- DVP/CONTROL PLAN The Design
Verification Plan (DVP) or the Process Control Plan
(PCP) considers the failure modes from the FMEA.
- INTERFACES The FMEA scope includes
integration and interface failure modes in both block
diagram and analysis.
- LESSONS LEARNED The FMEA considers
all major "lessons learned" (such as high warranty,
campaigns, etc.) as input to failure mode identification.
- LEVEL OF DETAIL The FMEA provides
the correct level of detail in order to get to root
causes and effective actions.
- TIMING The FMEA is completed
during the "window of opportunity" whence it can most
effectively influence the product or process design.
- TEAM The right people are adequately
trained in the procedure and participate on the FMEA
team throughout the analysis.
- DOCUMENTATION The FMEA document
is completely filled out "by the book," including "Action
Taken" and final risk assessment.
- TIME USAGE Time spent by the
FMEA team is an effective and efficient use of time
with a value added result.
For more information about the 10 FMEA quality objectives,
please refer to the article "Key Factors for Effective FMEAs,"
in Volume 6, Issue 2 of Reliability Edge:
http://www.reliasoft.com/newsletter/v6i2/fmea_factors.htm
The following FMEA audit procedure is excerpted from
the book Effective FMEAs (John Wiley & Sons, ©
2012, all rights reserved). It is a proven procedure and
has helped hundreds of companies improve their FMEA process.
It builds on the ten FMEA quality objectives.
The FMEA quality audit procedure is an essential part
of ensuring good quality FMEAs. FMEA quality audits are
in-person audits of completed (or nearly completed) FMEAs,
done with the FMEA facilitator and the FMEA core team present.
The audit can be done on a pre-scheduled or random basis.
Someone, who is skilled and experienced with the content
and quality of good FMEAs, performs the audit, from either
management or an FMEA subject matter expert. Here is the
procedure.
Each of the ten FMEA Quality Objectives have a corresponding
"How to audit" recommendation. In a nutshell, an FMEA auditor
reviews the FMEA results with the FMEA team against each
of the FMEA Quality Objectives, one by one, using the "How
to audit" recommendation. Each quality objective is evaluated
for how well it is achieved. This evaluation can be done
on a yes/no basis or a variable evaluation, such as high,
medium or low. The estimated time is one hour for this audit,
about 5 minutes per FMEA Quality Objective. The results
of the audit provide valuable feedback to improve future
FMEAs. The focus is on improving the FMEA process, not on
the person or team doing the FMEA. The auditor is looking
for specific process-related issues that underlie deficiencies
in achieving the quality objectives, such as lack of training,
procedure, facilitation skills, standards, resources, support,
etc. Action items from the FMEA quality audit should be
documented and pursued to improve the overall FMEA process.
Do not expect to achieve all ten FMEA quality objectives
instantly. Rather, work to maintain steady improvement.
Auditing Quality Objective # 1
The FMEA drives product design or process improvements
as the primary objective.
How to audit: Look at the recommended actions
and observe whether or not most of them drive design improvements
(in the case of a System or Design FMEA) or process improvements
(in the case of a Process FMEA). Talk with the team to ensure
focus was on improvements to design or process.
Auditing Quality Objective # 2
The FMEA addresses all high-risk failure modes with
effective and executable action plans.
How to audit: Review high severity and high
RPN issues to see if the corresponding recommended actions
are adequate to reduce risk to an acceptable level. Talk
with the team to ensure they are satisfied all high risk
is addressed and no important concerns are left unaddressed.
One way to do this is to ask the subject matter experts
for their two or three biggest concerns on the project,
and then to verify that these concerns are adequately addressed
in the body of the FMEA.
Auditing Quality Objective # 3
The Design Verification Plan & Report (DVP&R) or
the Process Control Plan (PCP) considers the failure modes
from the FMEA.
How to audit: Review the recommended actions
to see if there are improvements to the Design Verification
Plans or procedures, or the Process Control Plans, based
on risk associated with current detection controls. Talk
with the team to determine if they had adequate representation
from testing and if the FMEA benefited from the testing
experience, and to learn whether the test regimens were
improved if the current detection controls were not adequate.
Auditing Quality Objective # 4
The FMEA scope includes integration and interface
failure modes in both block diagram and analysis.
How to audit: Review items, functions, failure
modes and other portions of the FMEA to ensure that interface
and integration issues were taken up and addressed within
the scope of the FMEA. Look at the FMEA Block Diagram to
verify. Talk with the team, inquiring how they ensured no
interface issues were missed.
Auditing Quality Objective # 5
The FMEA considers all major "lessons learned" (such
as high warranty, campaigns, etc.) as input to failure mode
identification.
How to audit: Review failure modes and causes
to ensure that they contain supplemental field failure data.
Preferably, there is a visual way to see which failure modes
are from field information and how they are addressed. Talk
with the FMEA team to ensure that the FMEA benefited from
field lessons learned and that high-risk issues from the
field will not be repeated.
Auditing Quality Objective # 6
The FMEA provides the correct level of detail in
order to get to root causes and effective actions.
How to audit: Verify that the level of detail
on higher risk issues is adequate to fully understand root
causes and develop effective corrective actions. Review
the different columns of the FMEA to see if the overall
level of detail is proper and adequate. Too much detail
shows up as endless pages of FMEA material, including areas
that no one on the FMEA team is concerned about; too little
detail shows up as under-defined functions, failure modes,
effects, causes or controls, or as areas of unaddressed
concern from one or more FMEA team members. Talk with the
FMEA team to determine how they addressed the level of detail
and ensured all concerns were included in the scope of the
FMEA project.
Auditing Quality Objective # 7
The FMEA is completed during the "window of opportunity"
whence it can most effectively influence the product or
process design.
How to audit: Review the timing of the FMEA
project against the product development process timing gates.
Verify the FMEA was started and completed in the proper
time frame for ensuring maximum value.
Auditing Quality Objective # 8
The right people, adequately trained in the procedure,
participate on the FMEA team throughout the analysis.
How to audit: Review the FMEA team membership
roster to ensure that there was adequate representation
from the various disciplines needed based on the type of
FMEA and the scope of the project. Check FMEA team meeting
records to ensure attendance was adequate at each meeting.
Talk with the individual team members to see if their input
was elicited in the decisions.
Auditing Quality Objective # 9
The FMEA document is completed "by the book," including
"Action Taken" and final risk assessment.
How to audit: Look at the FMEA to see if the
various columns were properly filled out and that FMEA best
practice procedure was followed. Talk with the FMEA team
to ensure they rigorously followed FMEA guidelines and practices.
Auditing Quality Objective # 10
Time spent by the FMEA team is an effective and efficient
use of time with a value added result.
How to audit: Talk with the FMEA team to see
if each member believes his time was well spent and a value
added result was achieved. If any issues arise, find out
why.
FMEA audits will help ensure that FMEAs are effective
in achieving quality and reliability objectives in your
company. It may help to see a critical analysis of an actual
FMEA to understand the characteristics of good FMEAs.
In the next Hotwire Hot Topics article, an actual
FMEA will be evaluated using the audit procedure described
above. Readers will be encouraged to practice auditing the
FMEA using the ten quality objectives. A "teaching analysis"
will be provided to demonstrate how well the FMEA achieves
each of the 10 quality objectives.
If you have questions or comments about this article,
the subject of FMEAs, or the book Effective FMEAs, please
send an email to the author at
Carl.Carlson@EffectiveFMEAs.com.
About the Author
Carl S. Carlson is a consultant and instructor in the
areas of FMEA, reliability program planning and other reliability
engineering disciplines. He has 30 years experience in reliability
testing, engineering, and management positions, and is currently
supporting clients of ReliaSoft Corporation with reliability
and FMEA training and consulting. His new book, Effective
FMEAs, is available on Amazon.com. Information
about the book and links to useful FMEA articles and
aids can be found at www.effectivefmeas.com.
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