Jidoka
(literally translated) means "Automation". Through shop usage at Toyota the word has taken on other
connotations. One meaning refers to the stopping
of a
manual assembly or production line when something goes amiss.
At
Toyota, every worker has the authority and the responsibility to stop
an entire line when a problem arises. The purpose is to bring
attention to the problem, regardless of how small, and focus
efforts on it. This forces a permanent solution.
It
has been an article of faith in automotive plants that an assembly
line must never stop. When Taiichi
Ohno first told supervisors to stop the lines when trouble
developed, they were incredulous.
Ohno tells
of two supervisors: one who followed orders and stopped the line
immediately when trouble developed and another who was reluctant
to stop the line.
At first,
the line that stopped frequently had lower output. After several
months, however, the situation reversed. The line that
rarely stopped still had the same problems. These problems stalled
productivity improvements and created rework that lowered
efficiency. The line that initially saw frequent stoppages found
that the stoppages had been reduced and overall efficiency
improved.
A
Cautionary Note
Jidoka
only works when the supervisors and operators have the skills and
experience to fix the problems. Jidoka, itself, only spotlights
the waste.
Employees should have at least twelve hours of training
in Root Cause Analysis, four hours in Process Mapping and six
months of intensive practice before Jidoka is employed.
References
MONDEN,
YASUHIRO, Toyota Production System, Third Edition, Industrial Engineering &
Management Press, Atlanta, Georgia, USA, 1998.
Jidoka
only works when the supervisors and operators have the skills and
experience to fix the problems. Jidoka, itself, only spotlights
the waste.
