Sustaining continuous flow also serves to surface any problem that would
inhibit that flow. In essence, the creation of flow forcesthe correction of problems,
resulting in reduced waste. We often use the analogy of a ship on a sea filled with
dangerous rocks. As long as the rocks, like problems, are covered with water, like
inventory, it’s smooth sailing. But if the water level is lowered, the ship can
quickly be demolished by running into the rocks. In most operations there are
boulders hovering just under the surface, so naturally we keep enough invento-
ry to hide the problems.
Ohno discovered that if he reduced the inventory, the problems surfaced, and
people were forced to solve them or the system was forced to stop producing. This
was a good thing, as long as the damage was not too severe and the people had
the capability to improve the process so that the problems did not recur. He also
learned that the system needed some minimal level of stability, or the reduction
of inventory would just result in a loss of production, as we saw in Chapter 4.
Connecting two or more processes into a continuous flow will increase the
severity of any problems and necessitate their elimination. Connected flow across
the enterprise means that production in the entirefacility—and perhaps across
multiple facilities—will be shut down if the problems are not corrected effec-
tively. Imagine the importance of equipment readiness, manpower availability,
and material supply when thousands of people all stop working if there is a failure!
At Toyota this occurs from time to time. The entire operation is connected, and so
within a few hours a problem with a main component will halt the entire facility.
Many organizations believe that this type of production stoppage is unaccept-
able. Stopping production is a sure ticket to the unemployment office. But Toyota
sees it as an opportunity to identify a weakness within the system, to attack the
weakness, and to strengthen the overall system. It is this counterintuitive think-
ing that perplexes bottom-line thinkers. The Toyota Way suggests that “failing”
and correcting the shortcoming is a way to improve results for the long term.
Traditional thinking, in contrast, is that success is achieved by never allowing
“failure” to affect the short-term result.
That said, the objective is not to entirely jeopardize performance. It is wise
to prepare for flow by eliminating major issues, and to move with careful intent
and understanding, beginning with planning, and developing the discipline for
solving problems. As the process improves, and develops capability, the control
parameters are compressed during the leveling phase to surface the next layer
of issues in an ongoing cycle of continuous improvement.
Why Flow?
Most often the failure of implementation stems from a misguided belief that suc-
cess is rooted in the application of lean tools (such as setting up the cell). We often
tour clients through lean plants, in some cases Toyota plants, and it’s interesting
Chapter 5. Create Connected Process Flow 81