Lean tools

Jidoka / autonomation

In French: Jidoka (autonomation)

Jidoka gives the machine — and the operator — the power to stop production as soon as an anomaly appears, so that the defect is treated instead of being passed on.

What it is

Jidoka is often translated as "autonomation", a portmanteau of autonomy and automation. Its origin is a loom designed by Sakichi Toyoda, which stopped by itself as soon as a thread broke: instead of producing metres of defective cloth until an operator noticed, the machine flagged the problem the second it occurred.

The principle extended to people: any operator can stop the line when they observe an anomaly. That is the role of the andon, the light or sound signal that calls for help and makes the problem visible to all.

The least obvious effect is economic. A machine able to stop by itself no longer needs to be watched: one operator can run several. Jidoka separates the work of the person from that of the machine, and that is also why it is one of the two pillars of the Lean house.

The four-step sequence

Detect the anomaly — stop — correct the immediate situation — then find and remove the root cause. The first three steps are often well executed; it is the fourth that is missing, and without it the stoppage will recur identically.

A jidoka stop is therefore not an incident, it is information. A line that never stops is not a line without problems: it is a line where the problems go on to the next station.

The common mistake

Granting the right to stop without putting in place what makes it practicable. If pulling the andon means exposing your team, being called to account or delaying a rate on which you are assessed, nobody pulls the andon — and management concludes that all is well. Jidoka is as much a matter of managerial reaction as of device: what happens in the two minutes after a stop decides whether the next one will take place.

On the shop floor — Food processing

On a packaging line, the number of reported stops tripled in the month after an andon was installed — and the customer complaint rate dropped. The problems did not appear at that moment: they became visible.

The other tools illustrated by this trade: food and beverage.

Frequently asked questions

What does jidoka mean?

The Japanese term joins the idea of automation to that of autonomy, which English renders as "autonomation". It refers to the ability of a piece of equipment, or of the person running it, to interrupt production itself as soon as an anomaly appears, instead of letting the defect continue on its way to an inspection further along.

What is the difference between jidoka and a poka-yoke?

The first is an organisational principle: it establishes who has the right to stop, at what moment, and what happens next. The second is a physical device that prevents the error or makes it impossible to ignore. The device serves the principle, it does not replace it: error-proofing devices installed with no right to stop and no treatment of causes do not make a system.

What is an andon for?

It is the signalling means associated with the right to stop: a lamp, a light column or a screen that displays the state of a station and calls for assistance. Its function is not to record the incident for later, but to bring it immediately to the attention of those who can come, while the situation can still be observed.