Jidoka, one of the lean production techniques, is in fact the technique that Toyota put into practice first. While they were still manufacturing weaving machines, they made the machine stop by itself when an error occurred. In this way they achieved a major improvement by preventing the error, which was causing a very large loss of labor and of product, from continuing.
In essence there is a possibility of an error at every workstation that produces a product or a service. The result of an error that is made is that the product or the service is defective. The point being spoken of here is that the error causes a defective product. In many studies we explain finding the root error and preventing it. Jidoka comes into play at exactly this point. As Toyota did above, autonomous systems keep the system from continuing when an error occurs, and the error is prevented from turning into a defective product.
We explained in our previous articles that Jidoka consists of certain principles. Today we will talk about the effects of these principles. Let us start with the first principle, "Stop when an error occurs." Let us begin by sharing a memory. I was shocked when I heard that a machine at one of our injection-molding customers was producing 48% defective product. It was obvious that this production could not continue, yet nobody was taking any measure. When I asked why, they said that production was only just enough for the customer, one for one, and that they could not stop. Yet if they had stopped just once, production could have at least doubled. An improvement related to the mold had to be made on the injection machine.
As you will understand from this, stopping when you detect the error means that you do not go on producing defective product; otherwise you go on by making the losses larger. This is very clear, is it not? If you insist on continuing the work and offer the customer as the reason, employees will also learn to ignore errors, and many other errors will continue without being corrected.
The second principle is to go to the source of the error. What we have seen many times in our past work are situations in which the job continues by repairing the error at the point where it was detected. As a result, we have come across many situations in which no measure is taken at the source of the error, the criteria have widened as well, and the "it'll do" concept has settled in. In other words, it is a fact we frequently encounter that either the defective product is not recognized at all and the product is treated as sound, or, when it is recognized, the situation in which no improvement is made in the processes under the "it'll do" concept is accepted as it is, and people say that it has been this way for years.
If we touch on the general effect again, stopping as a result of detecting an error, through Jidoka applications, will create an ideal environment for making problems more visible and for encouraging people to solve those problems. This is a good result that we expect from Jidoka.
