Page 118 - Design for Six Sigma a Roadmap for Product Development

Product Development Process and Design for Six Sigma 93

■ Finalize requirements:
Establish minimum requirement definitions.
Identify and fill gaps in customer-provided requirements.
Validate application and usage environments.

■ Identify CTSs as critical-to-quality (CTQ), critical-to-delivery (CTD),
critical-to-cost (CTC), and so on.
■ Quantify CTSs.
Establish metrics for CTSs.
Establish acceptable performance levels and operating windows.
Perform flowdown of CTSs.
DFSS tools used in this phase include:

■ Market/customer research
■ Quality function deployment
■ Kano analysis
■ Risk analysis

3.7.2 Phase 2: Characterize design (C)
Step 1: Translate customer requirements (CTSs) to product/process func-
tional requirements. Customer requirements, CTSs, give us ideas
about what will satisfy the customer, but they can’t be used directly as
the requirements for product or process design. We need to translate
customer requirements to product/process functional requirements.
QFD can be used to add this transformation. Axiomatic design princi-
ple will also be very helpful for this step.

Step 2: Generate design alternatives. After the determination of the
functional requirements for the new design entity (product, service, or
process), we need to characterize (develop) design entities that will be
able to deliver those functional requirements. In general, there are two
possibilities:

1. The existing technology or known design concept is able to deliver
all the requirements satisfactorily; this step then becomes almost a
trivial exercise.
2. The existing technology or known design is not able to deliver all
requirements satisfactorily; then a new design concept needs to be
developed. This new design could be “creative” or “incremental,”
reflecting the degree of deviation from the baseline design. The
TRIZ method (Chap. 8) and axiomatic design (Chap. 7) will be help-
ful in generating many innovative design concepts in this step.