Page 202 - The Toyota Way Fieldbook

178 THE TOYOTA WAY FIELDBOOK

TRAP
Stack Lights May Not Be Effective Andons
When the concepts of andon and jidoka made their way into the
general public, we started to see “stack lights” appear on machines.
These are usually a small set of lights with three or four different
colored lights stacked in one unit. This was to serve the purpose
of an andon. There are a few problems. First we see that there is a
general disregard of the lights. We can look across the work area
and see many lights lit with different colors. What we don’t see is
any specific response to the lights. The proliferation of lights has
desensitized people. Also, the lights generally have no indication
as to what they mean. When we ask people to explain the meaning,
we get a variety of answers. Finally, there is no audible aspect to the
lights. It’s relatively easy to ignore a light, but more difficult to
ignore a buzzer. (By the way, Toyota’s andons have a different tune
for the different conditions indicated. The supervisor call, or line
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stop, is Beethoven’s classic melody “Für Elis,” for example.)
Sadly, this is a classic case of the application of a lean tool with-
out a deep understanding of the purpose, and without hansei to
reflect on the shortcomings. People falsely believe that because
they have the lights, they have andon, or jidoka. You must eval-
uate to determine whether the tools you implement are serving
the function for which they were intended.

The Problem-Resolution Cycle

Before you try to build a system, it is important to understand the full cycle of
the problem, from recognition through resolution and prevention. Figure 8-3
depicts the problem-resolution cycle visually. This cycle is typical within Toyota.
This entire cycle is repeated many times throughout the day. Problems are con-
stantly being surfaced and corrected, with minimal interruption to the production
flow (“fixed position stop” is discussed in the section on “Minimizing Line Stop
Time,” and Figure 8-4 illustrates the fixed position stop system). Think of these
steps as a “chain of events” with each event triggering the successive event as nec-
essary. This process is coordinated and orchestrated as well as any basketball team
executing a certain play.
1. Recognition. The first step of the process is the recognition that an abnor-
mal situation exists. Recognition is possible because there are established

This piece is designated WO o 59, or Without Opus number 59
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