Aug 19 2015
Jidoka (自働化) isn’t just “stop and fix” or “stop and call.” It is a complete approach to automation that includes building in the ability of a machine to stop when it malfunctions but also includes many other things. Sakichi Toyoda’s Type-G loom didn’t just stop when the yarn broke, it also had automatic shuttle change, which reduced the need for human intervention in its normal operations, and was a breakthrough that had eluded everybody else.
The goal wasn’t switching shuttles but switching bobbins within shuttles, which nobody managed to automate successfully. Toyoda was the first to realize that you could prepare shuttles with full bobbins off line, and that switching shuttles was easier than switching bobbins in a flying shuttle. It was similar in concept to replacing reels with cassettes in tape recorders.
The difference between Toyota’s Jidoka and automation as originally conceived at Ford in the US in the 1940s can be seen in the total absence of consideration of the role of people in the American literature on automation. Jidoka as “automation with a human touch” also means automation with due consideration of production lines as human-machine systems.
A dramatic example I remember seeing in a Japanese auto parts plant was a fully automated cell with old machines where you could tell that various retrofits, including robots, had gradually taken over the routine work done by operators. Next to this cell was a brand new one that looked very different but had been built based on the lessons learned in the old one.
You can call it separating people and machines but, rather than just a separation, I see it as thinking through the way to effectively use people with automated systems. I understand you can organize concepts in many different ways and I have recently seen Poka-Yoke/mistake-proofing as part of Jidoka, but I would not put it there, because Poka-Yoke is about manual operations. Poka-Yoke belongs instead as a quality improvement tool, under the Quality management header.