Page 255 - Design for Six Sigma a Roadmap for Product Development

Quality Function Deployment (QFD) 225

Another group of “unspoken” WHATs can be categorized as innova-
tions or delighters. These pleasant surprises increase customer satis-
faction in nonlinear fashion. For example, in the automotive industry,
van owners were delighted by the second van side door and by baby seat
anchor bolts.
Design features may change position on the Kano model over time.
In the 1990s, the second side door in a caravan was a pleasant surprise
for customers. Now, on most models, the second door is standard and
expected to be installed without a specific request. The ideal DFSS
project plan would include all three types of quality features: excite-
ment quality (unspoken latent demands), performance quality (spoken
and one-dimensional), and basic quality (unspoken or assumed).

7.6 The Four Phases of QFD
In the DFSS algorithm, including QFD, no single chart can accom-
modate all the information traded by the team to plan, control, and
document their entire project development cycle. Targets and toler-
ances of the HOWs must be specified, team tasks must be clarified,
and potential failures must be identified and countermeasures taken.
In the DFSS algorithm, the QFD house-of-quality (HOQ) matrices
have to be developed to plan the design and its production processes
and controls and the procedures. Our experience indicates that an
average QFD study will require many more charts than the four phases
of QFD may propose.
The first QFD translates the customer needs and expectations into
the CTSs and later into design actions. This conversion is completed by
constructing a new relationship matrix (HOQ phase 2) on which
WHATs are the CTSs and their target values from the previous matrix.
The HOWs and HOW MUCHs of each matrix are progressively deployed
as WHATs on the matrices that represent the next phase of the develop-
ment cycle.This conversion of HOWs to WHATs is continued from design
planning to process planning and finally to production planning.
This procedure should be continued until completion of production
planning. As illustrated in Fig. 7.2, this entails deploying the customer
requirements into CTSs, which are then deployed to design parame-
ters and then to process variables. At this point production require-
ments can be developed and QFD process is completed. Although only
four charts are shown in the illustration, we suggest using the first
phase of QFD and then proceeding with axiomatic design zigzagging
process for cascading requirements. This will produce the hierarchy of
the physical structure while employing design axioms.
QFD provides an efficient method to funnel the list of available
options. Important, new, difficult, and high-risk HOWs are identified