Page 100 - Design for Six Sigma a Roadmap for Product Development

Product Development Process and Design for Six Sigma 75

1. Value-added. These tasks are the ones that really move the product
design forward and create values that external customers are will-
ing to pay for the job done. The examples of tasks in this category
include drafting new designs, conducting design simulation for
improvement, and creating application software codes.
2. Nonvalue-added but necessary. These tasks are the ones that may
not move the product design forward and may not create values
that external customers are willing to pay for, but they are neces-
sary under current circumstances. The examples of tasks in this
category include design gate reviews, team coordination meeting,
and validation testing.
3. Waste. These tasks are the ones that do not move the product design
forward, and they have no value for external customers. These
tasks can be identified and eliminated. The examples of this cate-
gory of tasks include time spent on moving from meeting to meet-
ing, voice mail checking, searching for information, and so on.

In lean task management, we will try to increase the ratio of value-
added time, and to decrease the ratio of nonvalue-added but necessary
and the waste, as illustrated in Fig. 3.9. Mascitelli stated that based on
industry survey, in an 8 hour working day, the average value added
hour is only 1.7 hours in the Western companies. However, Toyota
claimed that its average value added time is more than 50%.

Focused working time with no interruptions. When people are doing
some work, it takes some time to achieve mental focus on the job, and
it takes some time to get even a small amount done. When people are
constantly interrupted, the productivity will be very low. Also, when
people handle several tasks, if they switch tasks very often, the
progress on each task will be usually slower than that achieved by
doing one thing at a time.

Value Nonvalue-added
added but necessary Waste

A lean
“future state”

Nonvalue-
Value added added
but necessary

Figure 3.9 Identifying and increasing value-added time in
product development.