A few years later, when I was working at Toyota, one fact called my attention at the engine assembly line: to my surprise, other than sophisticated torque control systems, I had seen in many engine assembly lines that Toyota was using very simple and cheap mechanical torque wrenches to ensure proper torque application.
I asked the assembly line leader why Toyota didn't use electronic or pneumatic devices. He told me that some time ago, Toyota had also run a similar problem solving project due to an oil leak issue.
I didn't know it then, but I was about to learn a more effective way to run a real problem-solving project!
Toyota had never considered any component as being part of the problem! Using the Jidoka concept, after the torque inspection failed, they immediately realized that there was an issue with the torque application stem and the assembly line stopped. The team in charge of solving the problem identified that the pneumatic system adopted to apply the torque over the fasteners was highly susceptible to variations within the air pressure lines and that jeopardized the stability of the whole process.
As a countermeasure, for small production volumes, they adopted a very reliable and well-known technology: a simple mechanical device that did not depend on air pressure.
Experts in the matter might say thatI am oversimplifying the technical part of this case, and indeed I am. It is not my goal to discuss the problem and solution, but emphasize that it merely took Toyota a few hours from the moment they detected the problem to put the countermeasure in place. Thanks to the Jidoka principle, they were able to stop the pro cess, narrow it down to the specific cause without being diverted by other.