Jidoka and Autonomation

Jidoka, as practiced at Toyota has several meanings. It may mean "automation with human intelligence"  (Autonomation). Jidoka also refers to the practice of stopping a manual line or process when something goes amiss.

Autonomation (Jidoka)

In one form, Jidoka uses limit switches or devices that shut down a process when:

• The required number of pieces have been made.

• A part is defective

• The mechanism jams.

The purpose is to free equipment from the necessity of constant human attention, separate people from machines and allow workers to staff multiple operations. This form of Jidoka relates closely to Shigeo Shingo's concept of Pokayoke.

Line Stop Jidoka

Jidoka, as applied to manned operations, refers to the practice of stopping the entire line or process when something goes amiss. This has important psychological and practical effects that contribute greatly to "continuous Improvement."

References

MONDEN, YASUHIRO, Toyota Production System, Third Edition, Industrial Engineering & Management Press, Atlanta, Georgia, USA, 1998.

HARRIMAN, FRED, www.fredharriman.com/services/glossary/jidoka.html, 2000.

OHNO, TAIICHI, Toyota Production System- Beyond Large Scale Production, Productivity Press, 1988.

The Confusion Over Jidoka

Taiichi Ohno considered Jidoka one of the two pillars of the Toyota Production System (TPS). Yet this aspect of TPS is mostly ignored in the West. When it is discussed, there is a lot of confusion and misunderstanding. There are several reasons, among them:

Japanese language (at least in everyday usage) seems less precise than English and the several meanings of Jidoka do not translate well.

For historical reasons, the autonomation concept seems less relevant today and more like ordinary good sense and practice.

The line-stoppage version of Jidoka requires a strong stomach and purity of mind that few managers (Japanese or American) possess.

The original meaning of Jidoka was "Automation" just as in English. It was written in Kanji as shown. 

The Kamigo Engine Plant developed many stoppage devices to halt automated machines. This became the word "Autonomation". It was pronounced as Jidoka but the Kanji had a subtle difference-- the addition of a few strokes representing humans or people. 

Later, the idea of stopping everything when something went wrong was transferred to manual assembly and the "Jidoka" term transferred as well. 

Other Articles In this Series

Stopping The Line
Autonomation

It seems to me that the 'Jidoka' pillar of TPS is only obscure to 'us'. This obscurity is a major reason why our 'lean' designs don't deliver the benefits. In implementing their 'Jidoka' pillar, Toyota thinks in a very different way to most companies, and that is why they consistently make quality improvements, and cost reductions.

The original Jidoka device (as far as I can tell) was Sakichi Toyoda's 1891 patent for an 'automatic' hand loom that stopped the shuttle if a thread broke. This avoided his mother having to wait until a hole appeared in the cloth, and then having to re-work the cloth to remove the hole. This principle was carried forward by Eiji Toyoda and Taiichi Ohno.

Jidoka also has a sub-title, "Quality built-in to the process". This seems to mean that the process inputs are controlled, and operators have authority to make adjustments within certain (control) limits. Variations outside control limits (monitored by devices on the equipment) are used to trigger a process 'stop'. This contrasts with the Western approach which is to control the outputs of the process (measure, inspect, check, etc.) and then react to any non-conformance in the product. In many cases, this does not trigger a process 'stop'.

Jidoka is not an obscure part of TPS - to Toyota! It has been obscured by 'the West' in two areas:

• The West sees this "Quality built-in" aspect as a sort of 6-Sigma/ISO 9000 approach. We tend not to design quality into the process, rather to measure the quality coming out of the process.

• We tended to believe Womak and Jones when they told us that 'Lean Thinking' was the Toyota Production System. In fact, they only told us about the JIT pillar of TPS, not the Jidoka pillar. I notice that Jim Womak is now sending out his e-mail circular saying that he sees process capability (or, rather, incapability) as letting down good single-piece flow designs!!

Automation is focused on labor reduction. Autonomation (Jidoka) is focused on quality improvement, and the independence of the man from the process. 

Automation increases technicality, Autonomation reduces technicality. This allows skill levels to be lower in similar processes when comparing East to West. Another cost reducer!

Little wonder 'we' invest billions in huge projects to automate and fail to reduce costs to Japanese levels, when they focus on quality improvement and labour reduction! (and use automation to replace humans solely where tasks are dirty, difficult, or dangerous)