Page 62 - Design for Six Sigma a Roadmap for Product Development

Six Sigma and Lean Fundamentals 39

new process standard. If the improvement is made by eliminating the
root causes of low performance, we need to keep track of process per-
formance after improvement and control the critical variables relating
to performance, by using control charts.

2.5 Lean Operation Principles
Lean manufacturing is a very effective manufacturing strategy first
developed by Toyota. During a benchmarking study for the automobile
industry in the late 1990s (Womack, Jones, and Roos 1990), it was
found that Toyota clearly stood above their competitors around the
world with the ability they developed to efficiently design, manufac-
ture, market, and service the automobiles they produced. The key focus
of lean manufacturing is to identify and eliminate wasteful actions and
use a greater proportion of the company’s resources to add value for
the customers. Lean production is first mentioned in this study that is
used to describe the efficient, less wasteful production system devel-
oped by Toyota, called the Toyota production system. Lean production
in comparison to mass production was shown to require one-half the
time to develop new products, one-half the engineering hours to
design, one-half the factory hours to produce, and one-half the invest-
ment in tools, facilities, and factory space (Monden 1993, Ohno 1990,
Shingo 1989).
Although the lean manufacturing approach was originally devel-
oped in traditional manufacturing industry, lean manufacturing
mostly deals with the production system from a process viewpoint,
not a hardware viewpoint. It has been found that most of lean man-
ufacturing principles can be readily adopted in other types of
processes, such as product development process, office process, and
service factory process. When these lean manufacturing principles
are applied to generic processes, we call them lean operation
principles.
The key objective of lean operation is to eliminate all process wastes
and maximize process efficiency. The key elements of lean operation
include the following items:

■ Waste identification and elimination in process
■ Pull-based production system
■ One-piece flow
■ Value stream mapping
■ Setup time reduction
■ Work cells
Now we are going to discuss these key elements.