Page 411 - Design for Six Sigma for Service (Six SIGMA Operational Methods)

370 Chapter Ten

Table 10.2 Process Efficiency for Various Processes

World-Class
Typical Process Process
Process Type Efficiency (%) Efficiency (%)
Machining 1 20
Fabrication 10 25

Assembly 15 35
Continuous manufacturing 30 80
Transactional business processes 10 50

Cognitive business processes 5 25

The most frequently used techniques in lean operation include the
following:
• One-piece flow
• Work cells (cellular manufacturing)
• Pull-based production
• Quick setup time reduction
We now discuss these in detail.

One-Piece Flow
As we discussed in Sec. 10.3.2, there are several types of manufacturing
processes, such as the job shop, batch flow shop, and line flow processes.
The job shop process is also called the “machine village,” which means that
similar machines are grouped together. The job flow patterns of such pro-
duction systems can be quite erratic and messy, as illustrated in Fig. 10.20.
The job shop process is featured by low utilization, long delays, high work-
in-process inventory, and a long lead time. The advantage of the job shop
process is that it can take a large variety of tasks.
Many service processes are also job shop processes. For example, in most
organizations, the departments are functionally grouped together, such as the
personnel, accounting, and benefit departments. If a new employee wants to
finish all his or her paperwork, he or she must go through all these
departments. In many organizations, paperwork has to be approved by many
departments, so each piece of paperwork will first go to one department, then