The Japanese word Jidoka, also called autonomation or even autoactivation, is broken down into 3 Chinese characters. The first “Ji” means ” works alone “. In other words, if he does something wrong or creates a defect, he has to stop alone. “do” means movement or work, and “ka” is the suffix ” -ation “1. Put end to end, Toyota defines it as ” automaton with a human mind ” and implies that machines and operations identify errors and take fast countermeasures2.
The principle of Jidoka dates back to 1902 with the inventions of Sakichi Toyoda. One of his inventions was a device for detecting the breakage of a wire and immediately stopping the machine. You could then replace the broken wire, turn the machine back on and especially solve the problem in the immediate order to prevent the fault from repeating itself3.
« Mr. Ohno used to say that a problem discovered by stopping the chain had to be solved the next day at the latest. Because when you produce a car per minute, you know that the same problem reappears the next day. » Fujio Cho, President of Toyota Motor Corporation
” If the operators have the possibility to stop the line, they will do everything to avoid having to stop it “. Akio TOYODA, President of Toyota (2015)
« A production line that never stops is either a wonderfully perfect line or a problem line. In the latter case, the fact that the line never stops means that the problems never go back to the surface. It’s very bad. It is essential to arrange a line so that it can be stopped at any time. This helps to prevent the generation of defective products, to mobilize the most competent staff to advance things and, finally, to strive towards the perfect line that never requires stopping. » Taiichi Ohno (1978)
It is a reflection on the ” manufacture ” of the quality and not the control that emerged. Thus the principles of the Jidoka were born redefining the role of employees:
« The machines have devices that detect anomalies and automatically stop their engines. The men, we give them the possibility to press buttons or to shoot the wire Andon, to stop immediately our assembly line. Each operator has the obligation to stop the chain every time it observes an anomaly. We entrust them with the responsibility of quality. They feel involved, they have the power to act. They know they’re important. -Alex Warren, executive vice president of Toyota Motor Corporation
The example of Toyota
For a long time, Toyota has understood that solving problems as they appear helps to be more productive and reduce waste.
« When I was at Ford, if you did not produce at 100%, you had to explain to the division. We never stopped the chain. Here, we do not produce at 100% of the time. The strength of Toyota, I think, is that senior management knows the benefits of Jidoka. They have experienced it and they want it to be applied. Since I’ve been at Toyota, I’ve never been criticized for stopping production and for safety and quality at the expense of manufacturing objectives. All they care about is what you do to solve problems and identify the causes and what help they can bring to you. -Gary Convis, director of the Georgetown Toyota plant
Specifically, at Toyota, each workstation has a chain stop system (button, wire…). When a problem appears, his workstation stops after 15 to 30 seconds. At a rate of 1mn per car, the production agent has between 7 and 10 minutes to solve the problem, because there is a ” Buffer Stock ” of 7 to 10 cars between each workstation. This allows you to have 7 to 10 minutes to solve the problem before the chain also stops on the other workstation. This problem resolution is done hand in hand between the operator and the team leader who is directly involved, and they must together implement the principles of Genchi Genbutsu.
Source: J. Liker (2004) – The Toyota Model: 14 principles that will make your business a success
The error is human
The observation on which the Jidoka is based is that despite all the good human will, the error is always possible and that whatever the number of control. The whole issue, in a logic of ” 0 defect is possible “, is not to increase or harden the controls but to devise a system that does not allow to produce defects.
The table below shows the human error rate for a number of tasks.
Source: J. Stephenson (2000) – System Safety
自動化 or 自働化?
Behind the writing of the term Jidoka, Ohno “hides” a deeper meaning than empowerment. Indeed, ” theoretically ,” The term empowerment is written in Kanji as such:
- Ji:自 for self
- Do:動 for movement
- Ka:化 that corresponds to the suffix ” ation “.
Be put to the end, the term Jidoka is written therefore: 自動化.
However, in the writing we know of the term Jidoka, we have always seen it written in the following way: 自働化
If we look more closely, there is a very slight difference in the Kanji of the medium. Ohno wants to show a deeper meaning to the term Jidoka has added an element to the left of the middle Kanji and thus creating the following contraction:
It has therefore incorporated the idea of human in the term and that we translate by ” machine that performs actions in autonomy without human intervention “.
But let’s go a little further. Playing on the words, Taiichi OHNO, by modifying the intermediate Kanji, incorporates a non-meaningless subtlety. Took individually, the middle Kanji to the following meaning:
- 動: Move, move.
- 働: Work.
Ultimately, what Taiichi Ohno wants to express through the use of this particular spelling is the idea of added value. The creation of added value is for Ohno at the center of the concerns and the Jidoka in one of the pillars.
1-A business culture
Implanting the Jidoka is primarily based on a quality culture where each employee needs to detect, communicate and resolve problems immediately. This culture must be part of a business strategy. To do this, the management Committee must implement A long-term strategy based on:
- A promotion and communication plan.
- Training: For example, the Toyota Supervisors ‘ training manual states that a ” foreman who stops the chain two or three times because of the same problem is not worthy of his function .” Toyota – 1973. This pressure from the Jidoka is also put more on the management than the operational4.
- Measurement and reporting indicators: problem solving time, number of Poka-Yoké set up, percentage of teams trained…
2-The tools of the Jidoka
The Andon system
The system Andon is a means of visual control allowing to know immediately the working state of the production. It helps to increase the level of responsiveness and to better communicate around problems.
Deploy Poka Yoké
The Poka Yoké is a technique of designing systems that do not generate errors. For example, the Shape of the scart socket does not allow it to be put in two different directions.
Set up the principles of Genchi Genbutsu
Design processes respecting the separation man Machine
The principle of man-machine separation is based on the observation that the machine cycles and the male cycles are not the same. Thus, the role of the operator must be reorganized so that it can concentrate on tasks with high added value, the machines now stopping alone to detect a defect.
Set up the tools of self-control
To help with the detection of problems and detection, we will set up the autoquality and the QA Matrix. These tools involve staff in the process and help with the change of culture.
1 – P. Dennis (2007) – Lean production Simplified
2 – Toyota Motor Corporation, Management Consulting Division (1995) – The Toyota Production System
3 – J. Liker (2004) – The Toyota Model: 14 principles that will make your business a success
M. Baudin (2007) – Working with machines
M. Pillai, C. Martin-Bonnefous, P. Bonnefous, A. Courtois (2011) – Production Management
B. Coriat (1991) – Thinking upside down: Work and organization in the Japanese company