Page 361 - Design for Six Sigma a Roadmap for Product Development

Theory of Inventive Problem Solving (TRIZ) 331

designed to illuminate the lunar surface ahead of the vehicle. However,
existing lightbulbs would not survive the impact of landing on the moon’s
surface. The most durable bulbs were ones used in military tanks, but even
those bulbs would crack at the joint between the glass and screw base dur-
ing tests. A new bulb design suitable for the application had to be developed.
The situation was reported to the program leader, Dr. Babakin, who asked,
“What is the purpose of the bulb?” The answer was obvious—to vacuum-seal
around the filament. The moon’s atmosphere, however, presents a perfect
vacuum. Therefore, Babakin suggested lamps without bulbs. This is the case
of identifying a redundant function.

9.8 S-Curve Analysis of Technical Systems
Based on the researches of the evolution histories of many technical
systems, TRIZ researchers have found that the trends of evolution of
many technical systems are very similar and predictable. They found
that many technical systems will go through five stages in their evo-
lution processes. These five stages are pregnancy, infancy, growth,
maturity, and decline. If we plot the time line on the horizontal axis
(X-axis) and plot

Performance
Level of inventiveness
Number of inventions (relating to the system)
Profitability
on the vertical axis (Y-axis), we will get the four curves in Fig. 9.5.
Because the shape of the first curve (performance versus evolution
stages) (Fig. 9.5a) has an S shape, it is also called an S-curve.

Pregnancy. For a technical system, the pregnancy stage is the time
between an idea’s inception and its birth. A new technological system
emerges only after the following two conditions are satisfied:

■ There is a need for the function of this system.
■ There are means (technology) to deliver this function.
The development of a technical system, the airplane, can be used as
an example. The need for the function of airplane, that is, to fly, was
there a long time ago in the dreams and desires of many people.
However, the technical knowledge of aerodynamics and mechanics was
not sufficient for the development of human flight until the 1800s.
The technologies for the airplane were available since the develop-
ment of glider flight in 1848 and the gasoline engine in 1859. It was
the Wright brothers who successfully integrated both technologies in
their aircraft in 1903—and a new technology got off the ground.