Page 88 - Design for Six Sigma a Roadmap for Product Development

Product Development Process and Design for Six Sigma 63

3.2.2 Anatomy of the product
development process
Our goal is to develop a superior product development process that
excels on all product development metrics so it can bring great revenue
to the company. To figure out what is the superior product develop-
ment process, we need to know how the products are designed.
Dr. Nam P. Suh (Suh 1990), a professor at the Massachusetts
Institute of Technology (MIT), proposed a model for the design process
in his axiomatic design theory. By observing how designers design
things, Suh stated that every design task is a “mapping process,” as
illustrated by Fig. 3.3.
For example, if what we want to achieve is to move people from one
place to another on the ground without consuming external energy,”
then the design engineers will have to figure out how we want to
achieve it. The design engineers may give you a design solution of a
bicycle. A product design project can be divided into many tasks in the
form of “Given whats, find hows.” Each of these tasks can be seen as a
mapping from one domain to another domain.
In Suh’s point of view (Suh 1990), the design world consists of four
domains: the customer domain, the functional domain, the physical
domain, and the process domain. The customer domain is character-
ized by the needs that customers are looking for a product to satisfy. In
functional domain, the customer domain is translated to functional
requirements. All products are developed to provide functions, that is,
jobs to do to satisfy customers. Functional requirements are specific
requirements for functions. For example, in automotive design, in the
customer domain, a customer may say that she wants a “faster car.”
This is one customer attribute, and the engineer needs to figure out
what she meant by “faster car.” Finally, by comparing competitors’
product performance, the engineer may figure out that faster car may

What we How we
want to want to
achieve achieve it

Mapping

Domain 1 Domain 2
Figure 3.3 Design as a mapping process.