I am a trainer and consultant in Lean Manufacturing, Six Sigma, quality management, and business management.
What Are Jidoka and Autonomation?
Jidoka, or autonomation, is one of the principles behind the Toyota Production System (TPS). It aims to give machines "human" intelligence so that they stop when something is wrong. It is one of the TPS principles that is least understood in the West, and it is not implemented as thoroughly as it should be.
Originally, Jidoka, as part of TPS, was about making automation more "human" and having machines that would stop and highlight a problem when it occurred rather than continuing blindly on with an operator sitting there monitoring everything that was happening. This concept was known as "autonomation" – automation with a human touch.
Later, the principle of stopping when something out of the ordinary occurred was applied not just to the machines, but to the whole production process, so Jidoka became the practice of stopping the whole process when errors occurred.
Origins of Jidoka and Autonomation
In much the same way that most of the Toyota Production System can be traced back to previous works and initiatives such as Ford’s original production lines, the birth of Autonomation and Jidoka can be traced back to before Toyota began to build cars.
Before Toyota became Toyota, the Toyoda family was busy trying to build their textile industry. Sakichi Toyoda designed a loom that automatically stopped when the thread either ran out or broke. This meant that the machine did not continue on blindly creating a piece of cloth that then had to be reworked or scrapped. This not only allowed them to reduce the amount of scrap and rework in their processes, but it also allowed them to have a single operator running several machines rather than sitting watching just one.
It is rumored that it was the sale of this patented technology to a textile company in Yorkshire in the UK that provided the capital that the Toyoda family required to start the Toyota Motor Company.
As the Toyota Production System progressed and Toyota grew, they began to realize that they did not have to fully automate a process at great expense if they could get many of the benefits of automation from simple machines with a little built-in intelligence that could inform the operators when something was going wrong. Thus Jidoka began to be implemented in earnest.
The machines were designed so that they would not need an operator to stand over them, constantly observing them to ensure nothing went wrong. They were imbued with "intelligence" so that they stopped when something occurred out of the ordinary or would not start if loaded in an incorrect way. This meant that the operators, instead of having to continually monitor the machines, would only have to interfere with them on an exception basis; thus, the operators could monitor several machines rather than just one.
Jidoka and Visual Management
Combined with aspects of visual management such as Andon lights, Jidoka allows everyone to quickly see any problems on the factory floor quickly and easily and come running to fix them.
This means that costs are lower as fewer people are required, and the levels of technology used are lower than full automation, so lower skill levels for the operators are required, again meaning cost savings.
How Does Autonomation/Jidoka Work?
As in the loom originally sold to the UK, machines were designed to detect abnormalities in their running conditions so that they were stopped, in addition to applying Poka Yoke devices and ideas to prevent operation if components were incorrectly loaded or missed, etc. Most of these ideas are very simple and inexpensive to apply and prevent the creation of defective materials which could then disrupt later steps in the process.
The whole point is to stop the process whenever there is a problem. That way, operators only respond to the machines to reload or to fix problems on an exception basis. This allows everyone to focus their attention on solving these problems to prevent them from occurring again.
The application of Jidoka across the whole process is a natural progression of this tool. Operators are given the authority to stop the entire process if there is a problem, which focuses everyone’s attention on problem resolution. In this manner, problems are resolved as quickly as possible and not ignored or worked around without resolution.
The Importance of Jidoka
Jidoka is one of the most important pillars of the Toyota Production System and, of course, Lean. It is only by combining Jidoka, respect for people, and Just in Time (JIT) principles that Toyota can truly achieve the success that they do.
Many companies in the west that are trying to implement Lean stop short of giving their operators and machines the ability to stop the whole production line when a problem occurs. Thus do not instill the urgency and discipline required to solve the root causes of the many problems that plague us.
A JIT system requires that all parts of the process be reliable and produce defect-free products when required. Any failure will cause the system to break down, so people must be empowered to solve problems when they are highlighted by Jidoka or Poka-Yoke devices.
By implementing Jidoka as part of your Lean system, you begin to drive out problems from your processes and achieve much higher levels of quality. Typically the use of Jidoka, Poka Yoke and other Lean tools will achieve far better results than the often quoted Six Sigma levels of quality.
Jidoka Line Stop
If you go into any Toyota Car Manufacturing plant around the world, you will be able to see that the operators are able to easily stop the line if they have a problem and have the authority and, in fact, are compelled to do so.
Stopping the line when a problem is encountered focuses the attention of all involved in actually solving the problem rather than just continuing to live with it. Most companies that I have visited over the years have operators that conduct their own unofficial rework or "workarounds" just so that they can aid management by keeping production moving.
We live with problems and fail to deal with them as we are often too scared of not making the numbers; yet if we solved the problems, we would be able to "make the numbers" so much easier and with a whole lot less effort on the part of everyone involved. However, we are often too worried about the initial impact that allowing line stops would have.
Jidoka and Poka Yoke
Poka Yoke or mistake-proofing is a technique that is part of Jidoka as well as being a stand-alone tool in its own right. The idea of Poka Yoke is to design the process in such a way that it is impossible to process or create defective materials.
This can be achieved through simple ideas such as profiled locations in fixtures that will only accept the correct components, pins that will show if holes are missing or blocked, simple sensors to check if components are present or correctly located, etc.
Poka Yoke devices should be simple and inexpensive. Often the best devices are those devised by the operators running the process. If you are having to spend vast amounts of money on devices, then you are probably not thinking hard enough or wide enough to solve the issue.
As with the autonomation aspects of a process or machine, Poka Yoke should be introduced at the process design phase, use tools such as Process Failure Mode and Effect Analysis (PFMEA) to highlight potential failures and then try to design them out of the process.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
© 2010 Tony