Page 243 - Design for Six Sigma a Roadmap for Product Development

Chapter
7

Quality Function
Deployment (QFD)

7.1 Introduction
In the context of DFSS, QFD is best viewed as a planning tool that
relates a list of delights, wants, and needs of customers to design tech-
nical functional requirements. With the application of QFD, possible
relationships are explored between quality characteristics as expressed
by customers and substitute quality requirements expressed in engi-
neering terms (Cohen 1988, 1995). In the context of DFSS, we will call
these requirements critical-to characteristics, which include subsets
such as critical-to-quality (CTQ) and critical-to-delivery (CTD). In the
QFD methodology, customers define the product using their own expres-
sions, which rarely carry any significant technical terminology. The
voice of the customer can be discounted into a list of needs used later as
input to a relationship diagram, which is called QFD’s house of quality.
The knowledge of customer needs is a “must” requirement in order
for a company to maintain and increase its position in the market.
Correct market predictions are of little value if the requirements cannot
be incorporated into the design at the right time. Critical-to-innovation
and critical-to-market characteristics are vital because companies that
are first to introduce new concepts at Six Sigma (6 ) levels usually cap-
ture the largest share of the market. Wrestling market share away from
a viable competitor is more difficult than it is for the first producer into a
market. One major advantage of a QFD is the attainment of shortest
development cycle, which is gained by companies with the ability and
desire to satisfy customer expectation. The other significant advantage
is improvement gained in the design family of the company, resulting
in increased customer satisfaction.

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