Page 182 - Design for Six Sigma a Roadmap for Product Development

Design for Six Sigma Project Algorithm 155

A conceptually weak design may have limited potential to succeed in
the use environment. The DFSS team should avoid or at least weaken
coupling through creative selection of the DPs. Highly coupled con-
cepts usually exhibit technical bottlenecks and conflicts, which on the
positive thinking side offer opportunity source for innovation. The
design and process failure mode–effect analysis (DPFMEA) exercise
identifies the design vulnerabilities as failure causes (Chap. 11).

5.7.1 Perform mappings (DFSS algorithm
step 6)
The mapping tool proposed here is the zigzagging process of axiomatic
design. The primary intention of its use is to fulfill the minimum set
of functions that in turn deliver the customer, corporate, and regula-
tory attributes. It is necessary to discuss and compare various solu-
tions for the functional requirements identified in the physical
structure as well as the methods of combining them to form a concep-
tual physical structure. This will decide both the feasibility and
compatibility of alternative solutions by narrowing down the concep-
tually feasible solutions to practically possible solutions of the prelim-
inary structure.
Functional analysis and physical synthesis are the premier activi-
ties performed in the C (characterize) phase of the DFSS algorithm. At
this stage of the project and after completing the detailing of the phys-
ical structure, the team should leap forward to perform the process
mapping, namely, process design.
The team needs to seek big ideas for competitive advantage and cus-
tomer delight, challenge conventional baseline physical structures
with innovative ideas, capitalize on design parameter new technolo-
gies, and cast preliminary definition of functional requirements (FRs);
design parameters and process variables; and minimize vulnerabili-
ties. In so doing, the team seeks to uncouple and simplify both struc-
tures. In this step, the black belt should foster an environment in
which “out of the box” thinking and brainstorming are encouraged uti-
lizing the conceptual methods offered by the DFSS algorithm. When
winnowing ideas, the black belt should foster a more structured, disci-
plined environment for the team as well as iterate back and forth
between expansion and contraction of ideas.

5.7.2 Uncouple or decouple selected
concepts (DFSS algorithm step 6)
The design process involves three mappings between four domains
(Fig. 5.13). The first mapping involves the mapping between customer
attributes and critical-to-satisfaction (CTS) metrics, followed by the