Page 107 - Design for Six Sigma a Roadmap for Product Development

82 Chapter Three

Iterate (if required)

Few Select Detail Test
concepts

Figure 3.13 Regular concept design process.

concepts; then we will select one seemingly good concept and move into
detailed design. After the design is ready, we will do some evaluation
test. If the test shows the concept is acceptable, we will move this con-
cept to the parameter design and prototyping stage. If the test shows
this concept is not acceptable, we will start another raw concept and
do another round of development; we may iterate this process until an
acceptable design is found. This regular design practice is illustrated
in Fig. 3.13.
On the other hand, the set-based design will simultaneously start
several concepts. The initial sets of concepts are coming from

■ Current knowledge
■ New technology from recent research and development efforts
■ Idea generation through brainstorming or TRIZ
This initial set of concepts should include at least one concept that
is relatively mature and reliable. After the initial set is selected, we
divide the engineers into teams, and each team works on one concept.
Each team will grow its concept by detailization, design evaluation,
and tests. It is very important that the set-based design stay in the
concept design stage; we can do some low-cost CAD (computer-aided
design) simulation, alpha prototype, small-scale laboratory test, and so
on. We don’t launch high-cost prototype buildings and validation tests
at this time. This will ensure that the set-based design approach will
not be expensive and time-consuming. Figure 3.14 illustrates how set-
based design works.
The whole set-based design will be subdivided into several ministages
during its progress; the concepts are evaluated and tested, and weaker