Jidoka is Japanese word which is usually translated to English as automation. But at Toyota, Jidoka refers to as the ability of production lines to be stopped in the eventuality of such problems as equipment malfunctions, quality problems or work being late, either by machines which have the ability to sense abnormalities or by employees.
Jidoka has the following significant benefits:
First, the passing on defect is prevented.
Second, equipment breakdown is prevented.
Third, the meaning of management is altered. Since the defects are stopped automatically, full time inspectors become unnecessary. Multi-machine handling and dramatic productivity increases are made possible.
Fourth, problems become clearly identifiable so that KAIZEN can be accomplished; for example, malfunction recurrence can be easily prevented, contributing directly to stable equipment operation and consistent quality.
At Toyota, following processes are treated as customers to be satisfied just as much as the customer who actually buys the finished product. To this end, every worker is inspector and every automated process contains an automated inspection.
An example of JIDOKA is the “fixed-position stop system.” Whenever a worker, in the course of working on the assembly line, encounters any king of abnormality, he pulls a rope located overhead. This lights up an ANDON, a large electrical signboard, which notifies the supervisor that there is a problem.
The line keeps moving until it reaches a “fixed position”, a point marking the end of one complete job, at which point it will come to a halt. The supervisor having rushed to the scene of the trouble after seeing the ANDON, assists in correcting the problem and pulls another overhead rope preventing the line from stopping and setting it back in motion if it has already come to a halt.
Another example is the use of fail-safe devices or POKAYOKE (invented by Shigeo Shingo) that help employees prevent themselves from making mistakes. Fail-safe devices make it impossible for defects to pass through, used especially on process where it is easy for the worker to make simple errors, such as choosing the wrong part incorrectly.
Important to all these activities is the concept of visual control. The state of work operations should apparent at a quick glance to anyone at the work-site. ANDON and other defect notification devices that can be seen and heard means of making simple visual control possible.
Just-in-Time and Jidoka are essential concepts that when properly put into practice make possible an extremely efficient system of production. The key is then “properly put into practice?” The best way to properly practice it is to standardized the work. It gives clear step-by-step guidelines to the workers how to perform each task in what most efficient, well-researched and established sequence of operation
We will shed light on standardized work in a separate post of this blog.