Page 420 - Design for Six Sigma a Roadmap for Product Development

Chapter
11

Failure Mode–Effect Analysis

11.1 Introduction
The failure mode–effect analysis (FMEA) helps DFSS team members
improve product and process by asking “What can go wrong?” and
“Where can variation come from?” Product design and manufacturing
or production, assembly, delivery, and other service processes are then
revised to prevent occurrence of failure modes and to reduce variation.
Specifically, the team should study and completely understand physical
and process structures as well as the suggested process mapping. Study
should include past warranty experience, if any; customer wants,
needs, and delights; performance requirements; drawings and specifi-
cations; and process mappings. For each functional requirement (FR)
and manufacturing and assembly process the team needs to ask “What
can go wrong?” They must determine possible design and process fail-
ure modes and sources of potential variation in manufacturing, assem-
bly, delivery, and all service processes. Considerations include
variations in customer usage; potential causes of deterioration over
useful product life; and potential process issues such as missed tags or
steps, shipping concerns, and service misdiagnosis. The team should
modify product design and processes to prevent “wrong things” from
happening and involve the development of strategies to deal with dif-
ferent situations, the redesign of processes to reduce variation, and
errorproofing (poka-yoke) of designs and processes. Efforts to antici-
pate failure modes and sources of variation are iterative. This action
continues as the team strives to further improve their design and its
processes.
In the DFSS algorithm, various FMEA types will be experienced
by the DFSS team. They are depicted in Fig. 11.1. We suggest using

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