There are not two but three definitions of the Japanese word jidoka, which students of kaizen and the Toyota Production System are likely to encounter. In fact there are two different jidokas. Coined by Taiichi Ohno as a play on words to turn the Japanese word for “automation” or “self-moving” into “autonomation” or “self-working”, the word jidoka and jidoka are pronounced identically, though written slightly differently in Japanese. Please see previous article for more on jidoka.
The “self-working” or “autonomation” term is used to kaizen two distinct problems.
First, to separate human work and machine work so that humans can do less non value added and more value added work within a given period of time. For example in a machining process that requires a person to open the door of a CNC machine, unload a part, loads another part and close the door, three out of four of these steps can be done by the machine. The only work that requires the human touch is loading the part, and perhaps doing a visual check. This type of automation is typically done in a low-cost manner.
Automating the final step of loading and inspection is higher cost, and not the kaizen way.
Second, autonomation is used to prevent processes from making error after error by building in en error prevention or detect-and-stop functions. Jidoka gives the process the equivalent of the human autonomic nervous system, which can respond to stimuli without conscious thought. This can take the form of sensors on a machine, lines of code that mistake proof a data entry field, or a button pressed by a person to alert the supervisor that the process cannot be performed correctly.
This photo from the kitchen of an apartment-hotel is an example of the first type of jidoka – low cost automation eliminating a step of human work.
When the door of the kitchen cupboard is opened, the lid of the trash can is lifted due to tension created in the string attached between the lid and the cabinet wall.
These types of 2-in-1 processes or mechanisms are called nagara in Japanese kaizen circles. The word nagara means “during” or “while doing” something, as in “She sings while she runs”. With a bit of creativity we can find motions, data entry tasks or mechanism that can be combined or triggered in such a way to turn manual processes into examples of jidoka – self-working low-cost automation.