Thursday 13 December 2018

What is Jidoka?

A Jidoka is one of the two pillars of the Toyota Production System along with just-in-time. Jidoka highlights the causes of problems because work stops immediately when a problem first occurs. This leads to improvements in the processes that build in quality by eliminating the root causes of defects.

Actually, jidoka is a tool for 100% control of the product during the manufacturing process, and not just when it is finish.

This objective is achieve through far-reaching Automation of the production process. It is assumes that through automation. We use reliable production processes and employees can focus on achieving performance targets.


On the one hand, automation helps visualize the process and, on the other hand, allows you to keep track of its parameters and possibly problems with production equipment (which accelerates the analysis and solving the problem).

The jidoka means Automation in conjunction with the work of man. The idea of Jidoka is build quality in the process and staff intervene only in the event of deviations to the perfect process.

In the event of a problem the production process is stopped and all employees are focused on solving the problem and bringing it to the initial state.

In the event of any problem with the engine operating parameters, is sent an alarm signal about the need to take corrective action or corrective measures.

Of course, such a system is necessary and is a complete aircraft, because we all know what the risk is accompanied by damage to the engine of the aircraft.

However, interestingly, supervision of performance engine does not perform the airline, which is the owner of the aircraft, but the control services of the company producing the engine, having knowledge in the topic analysis engine parameters.

The concept - Built in Quality at the Source

Jidoka or automation as it is often translated to, really refers to “Built in Quality at the Source” or even more simply – Don’t pass defects on. Many people forget that high quality and Just In Time go hand in hand. There’s no sense reducing lead times just to move defects faster through the value stream.

I like to think of Jidoka as three things:

  1. Don’t accept defects

  2. Do not make defects

  3. Don’t pass defects on

The origins of Jidoka go back to the original Toyoda (correct spelling of the family name) family Weaving Loom business. Before they became famous for making automobiles, the family was in the business of making weaving looms that had a reputation for making cloth of very high quality levels.

In the late nineteenth century, people used to sit and watch the weaving machines make cloth waiting for any broken threads which would lead to defects in the cloth. When they saw a broken thread they would stop the machine, repair the thread and restart the machine. Imagine a job like this, watching a machine do the work and reacting only when there was a problem. What a waste.

Toyoda saw this and invented a method whereby the weaving loom would self-detect a break in the thread, stop and alert the operators. The operators could then repair the thread and restart the weaving loom. Now one person could operate many looms and the looms would produce only cloth of the highest quality.

This is where the term Jidoka came from. Automation – automation or machines but with a human touch. Ones that can self-detect errors, stop and alert the operator. Now machines can do what they do best which is detecting defects and humans can do what they do best which is problems solving.

Implement it to lean time

By implementing Jidoka, we implement a system that prevents defects from being sent to the next person or operation in the value stream. Now we can begin to introduce JIT and cash in the benefits of reduced inventory and lead time.

Today, this post deals with the second bullet - Don’t make Defects. This can be broken down into a process which has four main parts to it:

  • Detect Defects

  • Stop

  • Call for help

  • Problem Solve

I see many people jumping on the bandwagon when they hear this but they tend to confuse the Stop step. While Stop accomplishes the goal of not passing defects on to the next operation, the parts of the process must work together. None of the steps works in isolation. I see many operations that wouldn’t run for very long if we kept stopping them every time the line produced a defect.

Operational & functioning with examples

Providing machines and operators the ability to detect when an abnormal condition has occurred and immediately stop work. This enables operations to build in quality at each process and to separate men and machines for more efficient work. Jidoka is one of the two pillars of the Toyota Production System along with just-in-time.

Jidoka highlights the causes of problems because work stops immediately when a problem first occurs. This leads to improvements in the processes that build in quality by eliminating the root causes of defects

Jidoka sometimes is called automation, meaning automation with human intelligence. This is because it gives equipment the ability to distinguish good parts from bad autonomously. Without being monitor by an operator. This eliminates the need for operators to continuously watch machines. Even and leads in turn to large productivity gains because one operator can handle several machines. Often term multiprocessing handling. The concept of jidoka originate in the early 1900s when Sakichi Toyoda, founder of the Toyota Group. Invented a textile loom that stop automatically when any thread broke.

Previously, if a thread broke the loom would churn out mounds of defective fabric. So each machine need to be watch by an operator. Toyoda’s innovation let one operator control many machines. In Japanese, jidoka is a Toyota-create word pronounce exactly the same (and written in kanji almost the same) as the Japanese word for automation. But with the add connotations of humanistic and creating value.

How to apply in manufacturing?

Jidoka technique can be applied in different ways; in almost all cases it depends on applied creativity to avoid a defective part to proceed in the process. Normally Jidoka techniques can identify with systems of automation of machines or the ability (and authority) the operator to stop the line. An automation machine is one that is connect to an automatic stop mechanism. To prevent the manufacture of defective products; in this way, joins machines a human touch or human intelligence.

the acclimatization also modifies the meaning of the use of the machine. When working normally don't need any operator; only when it stops as a result of an abnormal situation required the attention of the staff. As a result, a single worker can attend several machines thus reducing the number of workers and increasing the performance of the production.

the diagram of the progressive steps and specific techniques can be applied to achieve a complete automation in machines. The ability to stop the line operator is a fundamental aspect of the Jidoka. Each operator can press a button to stop production when it detects defects or irregularities. When the operator presses the button, a signal (andon) indicates the problem and alert to all the companions of the section of the difficulties of the operation assigned to the operator. This system of lights, allows communication between operators.

Practical Solutions

In practice it works in the following way. A green light means that there are no problems. One amber indicates that the production is lagging behind. As a result of a problem, but the operator that it has detect. It is able to meet him personally. A red light indicates the detection of a serious problem. The process is paralyze so that fellow and the own maintainer should contribute strongly to find a feasible solution.

An example that combines both techniques is use in some factories in the automobile sector. Where workers walk alongside a moving assembly line. It having a limit time to run your job. If this walks beyond the set distance. It will step a mat that will trigger a mechanism that will stop the Assembly line.

Step on the mat means that it has detect a problem, cause of the delay in their tasks. When the mechanism is activate and the line stops, responsible for section along with the operator. It will have a time to solve the problem and launch again the line.

What can be key points?

Another key point of the Jidoka techniques is the self-inspection or inspection "fool-proof" system, known as poka-yoke in Japanese. It's a machinery or devices which, once installed, avoid defaults to 100 percent even if there is human error.

In other words, it's that "errors not must result in defects and much less progress. The poka-yoke are characterize by their simplicity. Simplicity mean small devices immediate action, often simple and inexpensive. Effectiveness (acting for themselves, in each repetitive action process, regardless of the operator). It have three functions against defects: stop them, control them and warn them. A poka-yoke design should start from the basis that must be cheap, durable, practical, easy to maintain, ingenious and, preferably, design by operators.

Jidoka and Lean Manufacturing tools

The first step of Jidoka is that of detecting an abnormality, so for autonomation the machine uses simple sensors to detect a problem and then stops and highlights the problems for the operator. For line stop the operator detects an abnormality and stops the line and highlights the problem for all to see on an andon board.

Other Lean tools use various aspects of visual management to highlight abnormalities, consider 5S; we identify the locations for tools, components and work in progress, if we see things that are not in their allocated place we have seen an abnormality and should take action. Why do we have missing tools? Why are additional stocks being stored where they should not be?

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