Page 28 - Design for Six Sigma a Roadmap for Product Development

6 Chapter One

According to the ASQ definition of quality mentioned above, the
characteristics of the new product or service should have the “ability to
satisfy stated or implied needs”; therefore, one key task of quality
assurance activity in this stage is to ensure that the newly formulated
product/service functions (features) should be able to satisfy cus-
tomers. Quality function deployment (QFD) is an excellent quality
method for this purpose.

1.2.3 Stage 2: Concept development
Product/service concept development is the second stage. This stage
starts with the initial concept development phase. It involves convert-
ing one or more options developed in the previous stage into a high-
level product concept, describing the product’s purpose, general use,
and value proposition. Next is the product definition phase. It clarifies
product requirements, which are the base-level functional elements
necessary for the product to deliver its intended results.
Several quality methods, such as design of experiment (DOE),
response surface method (RSM), axiomatic design, and TRIZ (theory of
inventive problem solving) are also very helpful in the product concept
development stage for enhancing functionality and reducing expected
cost. Those methods are also helpful in developing a robust product
concept to ensure a final product that is free of deficiencies.

1.2.4 Stage 3: Product/service
design/prototyping
The third stage is product design/prototyping. In this stage, product/ ser-
vice scenarios are modeled and design principles are applied to generate
exact detailed functional requirements, and their actual implementation
and design parameters. For product design, design parameters could be
dimension, material properties, and part specifications. For service
design, design parameters could be detailed organization layout and spec-
ifications. The design parameters should be able to provide all the detail
necessary to begin construction or production. For product development,
after product design, prototypes are built to test and validate the design.
If the test results are not satisfactory, the designs are often revised.
Sometimes, this build-test-fix cycle is iterated until satisfactory results
are achieved. Besides physical prototyping, computer-based modeling and
simulation are also often used and sometimes preferred because they are
less costly and more time-efficient. During this stage, manufacturing sys-
tem design for the product is also conducted to ensure that the product
can be manufactured economically.
For quality assurance, it is clear that the key task of this product
design/prototyping stage is to formulate the set of design parameters in