Page 219 - How To Implement Lean Manufacturing

Cellular Manufacturing 197

When cells are arranged in a C or U shape, worker communication is facilitated. For
example, all workers are in proximity to one another, so worker interaction is encour-
aged. Worker interaction to assist in cross training and worker interaction to assist in
problem solving are just two such benefits. This proximity just makes communication
much simpler. They are also not only able to communicate better but assist each other
as well.
The typical U-cell situates the first and last work stations near each other. This
makes cell supervision much easier and gives everyone a better sense of work comple-
tion. Also, in the typical U-cell, workers usually sit or walk in the center of the cell. This
frees up the exterior of the cell to supply materials to the cell more easily.

Two Hidden Benefits of Cells
All of the items listed earlier are benefits, but in my experience I have found there are
two major benefits of cellular manufacturing that are seldom mentioned, but that are
very real, very positive, and very powerful.
First, the very nature of a cell creates a team with a sense of flow and synchroniza-
tion not seen in flow lines. In the flow line, you have two neighbors; in the cell, every-
one is in close proximity. The personal dynamics are changed considerably, leading to a
feeling of a group, of a team. The team concept is very powerful and there is a real sense
of assisting each other. In the cell, since the process is all around the worker, there is a
sense of flow and a sense of synchronization that is not present in the flow line. We have
documented cases that show this sense of flow and synchronization actually creating a
faster pace in the cell with reduced cycle times. We have found that it is not uncommon
for cells to reduce cycle time by 10 and even 20 percent as they mature. I have often
witnessed this cycle-time improvement in cells, yet I hear many engineers attribute it to
training and worker maturity. These same engineers, however, cannot explain why we
do not see the same benefits in a flow line as it matures.
Nevertheless, the greatest benefit of cells is a well-kept secret. Cells are a tremen-
dous tool to assist in reduction of variation.
I will later describe a case study of a high-volume production flow line that was
converted to cellular production. The plant achieved the rate modulating benefits ear-
lier mentioned, but in addition—with less staff and the same equipment—the cellular
option, compared to the flow line, was able to improve production by over 63 percent.

The Gamma Line Redesign to Cellular Manufacturing

The Background
The Gamma Line was a 21-station flow line with a 16-second cycle time. The first 16
stations were all manual assembly, followed by two tests and three packaging stations,
which utilized some expensive test and packaging equipment. Material was delivered
to one side of the 200’ long assembly line, the same side on which the workers were
stationed. Each station was staffed with one worker. The first 16 stations had almost no
automation; the most sophisticated tools were some ergonomic screwdriver stations. It
was a highly labor intensive production line.
Since most of the skills were very basic, the operators would learn all 21 stations in
less than six months with little effort or inconvenience to the work schedule. They had
an aggressive operator cross-training program.