Page 209 - The Toyota Way Fieldbook

Chapter 8. Build a Culture That Stops to Fix Problems 185

The first item, to check the incoming work, can be accomplished while the
part or the operator is in motion. For example, when the operator is completing
the work cycle and returning to the next vehicle, she can visually check specific items
as she walks. When a part is picked up, it is not picked up absent-mindedly, it is
picked up with intent—the intent to verify that it is the correct part and that it
is defect free. This inspection is an expectation for the correct performance of the
job. These are not typical thorough inspections; they are very quick and specific.
Thorough 100% inspections are done at the end of any subassembly or major
process like body welding, body paint, or chassis production.
Targeting specific areas with a history of problems will increase the effective-
ness of this checking process (use the data!). Other inspections can be performed
as a part is being installed or removed. Make a point of training people to look
at a specific location when performing the work. Chapter 11 has more details on
job instruction training, the method Toyota uses to train employees.
In a similar manner, each person can check his or her work. Work is checked
as it is removed from the machine or handed to the following operation. Specific
quality “key points” are identified, and operators check them. For critical opera-
tions, or tasks that have had a history of missed steps, a yoshi is used. (Pronounced
“yosh,”it is similar to a pilot calling “Check” while going over the preflight
checks.) The standardized work dictates that upon completion of the task, the
operator will point (yes literally!) at the part and call out “Yoshi,” signifying “I
have checked this item.” The pointing provides a visual cue to leaders that the
check step is actually being performed (aiding in the auditing of standardized
work). If this inspection were only visual, it is not possible to see if a person
actually looked as instructed. Also, the physical act of pointing requires inten-
tion, and the intentional act causes the brain to engage. A step is less likely to
be omitted if a yoshi is used. Asimilar process on parts where color marking
does not matter is to use color markers and physically mark each place where
a check has been done. The act of making the physical mark helps avoid miss-
ing checks.
Of course, one of the primary purposes of stopping the line is to prevent
passing defects to following operations. Even with this extensive system and
support available, it is one of the more difficult ideas to instill. People seem to
have an aversion to admitting failure or incapability. One of the great benefits of
small batch production is that if a defect is missed at one station and subsequent
operators are checking incoming work, there will be a very short feedback loop
from the time when the problem is created to the time when it’s discovered at a
downstream operation. It might be a matter of one hour or less, for example,
between when a welding operation is performed on a Toyota car body and when
someone trying to install parts notices a bad hole position. In a traditional large
batch operation the feedback loop time could be a week or more.