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Table of Contents
                            Front cover
Chapter 1. What Is an FMEA?
Chapter 2. What Is the Purpose of and FMEA?
Chapter 3. ISO 9000, ISO/TS 16949, and FMEAs
Chapter 4. The FMEA Process
Chapter 5. The FMEA Team
Chapter 6. FMEA Boundaries of Freedom
Chapter 7. Product/Design versus Process FMEAs
Chapter 8. Ten Steps for an FMEA
Chapter 9. FMEA Case Study
Chapter 10. When and Where to Use FMEAs
Appendix 1: Creating a Process Flowchart
Appendix 2. Brainstorming
Appendix 3: Reaching Consensus on Severity, Occurrence, and Detection Rankings
Appendix 4. Examples of Custom Ranking Scales*
Appendix 5: Process Improvement Techniques
Appendix 6: ISO/TS 16949 Requirements Referencing FMEAs
Appendix 7: Alternative FMEA Worksheets
FMEA Glossary of Terms
Back cover
Document Text Contents
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Chapter 9

FMEA Case Study

�is example of a design/product FMEA involves a manufacturer of �re extin-
guishers. �e company developed a new extinguisher for home use. It wanted to
make sure the extinguisher would be e�ective and would not cause any problems
when used. �e consequences of a faulty extinguisher could be life-threatening.

A team of �ve employees was formed to work through the FMEA process.
�e team included a design engineer who helped develop the extinguisher, the
second-shift manufacturing supervisor, the �rst-shift quality technician, the
purchasing manager, and the sales and marketing manager. �e design engineer
was appointed the team leader, and the members decided to name their team the
�Fire Extinguisher FMEA Team.�

�e team boundaries were to complete the FMEA, including making
improvements. �e team was given a $5,000 budget and could request help from
within the company to tap into outside team members� expertise. �e deadline
for project completion was April 15, at which time another team would be formed
to conduct a process FMEA.

Case Study Step 1: Re�iew the Process
All team members were given a blueprint of the �re extinguisher to review.
�e design engineer brought a prototype extinguisher to the �rst meeting and
demonstrated how it worked. He also handed out a product speci�cation sheet.
Everyone on the team was given an opportunity to operate the extinguisher,
and several good questions were asked and answered regarding the similarities

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42 ◾ The Basics of FMEA

to existing models. For example, the product manager demonstrated how the
extinguisher worked, highlighting the di�erences in operation between the new
and existing models. One participant asked if this extinguisher would work
the same for left- and right-handed people as do the existing models. Another
wanted to know the bene�ts of the rounder shape of the canister.

�e team also used the FMEA Team Start-Up Worksheet (see Figure 9.1) as
a checklist to make sure they understood their boundaries of freedom and the
scope of the project.

Case Study Step 2: Brainstorm Potential
Failure Modes
As suggested in the step-by-step FMEA guidelines, rather than dealing with the
entire product at once, the team broke analysis of the product design into man-
ageable chunks. �e most logical breakdown was into the key components of the
extinguisher: the hose, the canister, the charge gauge, and the valve mechanism.
�e chemical agent in the extinguisher was excluded because another team had
included it in an FMEA about six months earlier.

�e team then brainstormed all of the potential failures for each of those
components. For example, with the hose, potential failures were cracks, holes,
and blockages. With the canister, one potential failure was that the canister
could be dented, and another was that the label might not be properly glued.
�ey listed the potential failures on the FMEA Analysis Worksheet and grouped
them by component (see Figure 9.2).

Case Study Step 3: List Potential Effects of
Each Failure Mode
Each failure mode was discussed, and the team agreed on potential e�ects for
each of the failure modes. While there was some disagreement about the likeli-
hood that a certain e�ect would occur, the team agreed to include all possible
e�ects. Members reasoned that if it was highly unlikely that the failure and
e�ect would occur, then the item would probably get a low RPN anyway.

�e team listed each potential e�ect next to the failure. If members felt that
several di�erent e�ects were possible, and anticipated that each might have a
di�erent ranking in at least one of the three ranking categories, they listed them
in a separate row.

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