Three men were especially prominent in creating the Toyota
Production System: Sakichi Toyoda; his son, Kiichiro Toyoda;
and a production engineer by the name of Taiichi Ohno.
 Sakichi Toyoda was the inventor of automatic looms who founded
the Toyota Group. He invented a loom in 1902 that would stop
automatically if any of the threads snapped. His invention
opened the way for automated loomworks where a single operator
could handle dozens of looms.
Sakichi's invention reduced defects and raised yields, since a loom
would not go on producing imperfect fabric and using up thread
after a problem occurred. The principle of designing equipment
to stop automatically and call attention to problems immediately
is crucial to the Toyota Production System. It is evident
on every production line at Toyota and at other companies
that use the system.
When the Toyota Group set up an automobile-manufacturing
operation in the 1930s, Sakichi's son Kiichiro headed the
new venture. Kiichiro traveled to the United States to study
Henry Ford's system in operation. He returned with a strong
grasp of Ford's conveyor system and an even stronger determination
to adapt that system to the small production volumes of the
Japanese market.
Kiichiro's solution was to provide the different processes
in the assembly sequence with only the kinds and quantities
of items that they needed and only when they needed them.
In his system, each process produced only the kinds and quantities
of items that the next process in the sequence needed and
only when it needed them.
Production and transport took place simultaneously and synchronously
throughout the production sequence — inside and between
all the processes. Kiichiro thus laid the groundwork for just-in-time
production, and he gets credit for coining the term "just
in time."
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Taiichi Ohno |
The man who did the most to structure the Toyota Production
System as an integrated framework was Taiichi Ohno. In the
late 1940s, Ohno — who later became an executive vice
president at Toyota — was in charge of a machining shop.
He experimented with various ways of setting up the equipment
to produce needed items in a timely manner. But he got a whole
new perspective on just-in-time production when he visited
the United States in 1956.
Ohno went to the United States to visit automobile plants,
but his most important U.S. discovery was the supermarket.
Japan did not have many self-service stores yet, and Ohno
was impressed. He marveled at the way customers chose exactly
what they wanted and in the quantities that they wanted. Ohno
admired the way the supermarkets supplied merchandise in a
simple, efficient, and timely manner.
In later years, Ohno often described his production system
in terms of the American supermarket. Each production line
arrayed its diverse output for the following line to choose
from, like merchandise on supermarket shelves. Each line became
the customer for the preceding line. And each line became
a supermarket for the following line. The following line would
come and choose the items it needed and only those items.
The preceding line would produce only the replacement items
for the ones that the following line had selected.
This format, then, was a pull system, driven by the needs
of the following lines. It contrasted with conventional push
systems, which were driven by the output of preceding lines.
Ohno developed a number of tools for operating his production
format in a systematic framework. The best known of those
tools is the kanban system, which provides for conveying information
in and between processes on instruction cards. |
