The First Jidoka
The automatic loom, invented by Sakichi Toyoda, the founder of Toyota, in the year 1902, can be considered as the first Jidoka example. In this innovation, if threads ran out or broke, the loom process was stopped automatically and immediately.
In the early days of assembly line mass production, work cycles were watched over by a human operators. As competition increased, Toyota brought about a significant change in this process by automating machine cycles so that human operators were free to perform other tasks. The Toyota Production System has many tools for efficient products and services.
Developed over the years, these tools aim at reducing human effort and automating machines to increase productivity. Jidoka is one such tool without which efficient manufacturing would practically be impossible, as of today. The article below explains all about the Jidoka process.
The Concept of Autonomation
- To begin with, understand that autonomation and automation are different from each other.
- According to the definition of autonomation, it is a 'self-working' or 'self-controlled' process. It is a feature that contributes to the Jidoka process.
- Automation is the process where the work is still being watched by an operator, where errors may still be apparent, and detection and correction take a longer period.
- Autonomation resolves two main points. Firstly, it reduces human interference, and secondly, it prevents processes from making errors. This has been enlisted below.
- Ordinarily, when a defect occurs, a worker detects it and later reports the problem.
- Autonomation enables the machine to stop the cycle when a defective piece is encountered.
- If all the processed parts or components are not picked up at the end of the cycle, the machine might face problems, and the process might halt, and it would take a while before the worker realizes that the process has been interrupted because of a minor error.
- In case of autonomation, if the previous piece has not been picked up during ejection, the machine gives a signal or stops the cycle all together.
An Introduction to Jidoka
The Evolution towards Jidoka
- Jidoka can be simply defined as 'humanized automation'. Autonomation is just another term for Jidoka.
- It is used in different contexts. It is mainly used to detect defects and immediately stop the production or manufacturing process. It fixes the defect and finds solutions so that the defect or error does not occur again.
- The concept, as mentioned before, was invented by Sakichi Toyoda. Its purpose is to reduce human error and judgment by automatic error detection and correction.
- It was developed to eradicate the wastage of time due to human observation of the process, transportation, inventory, correction of defect, etc.
- Now, with Jidoka, production lines have become significantly more efficient, and the wastage of goods and inventory have been reduced too.
Other Toyota Tools and Terms
- You need to keep in mind is that Andon, Poka-yoke, Just-in-time, etc., are all tools invented by Toyota. Jidoka is also one of these tools, and it encompasses some of the others as well, like Andon and Poka-yoke.
- Jidoka was developed to minimize errors that may have been caused due to human observations.
- Remember that Andon is not an example of jidoka, but an important tool. It displays the current state of work―whether the process is smooth, or it has any malfunction, or if there are product glitches, etc.
- The relation between Andon and Jidoka has been explained further in the article.
- Similar to Jidoka, Just-In-time is another important tool, and is one of the crucial pillars of TPS.
- It adheres to what product is required, when it is required, and how much is required.
- The 'takt time' is an important principle―it refers to the time that should be taken to manufacture a product on one machine.
- Line Stop Jidoka is a term that applies to the process in automotive manufacturing plants.
- It is called so because it interrupts and halts the entire line (process) when a defect is found out.
The Elements of Jidoka
- It is one of the important elements of Jidoka.
- The basic principle of Genchi Genbutsu is to actually see the problem. It entails going to the root source of the problem.
- This is an important step in the Jidoka process―to find out why the defect occurred in the first place.
- As stated in the previous section, Andon is a visual representation of the current process.
- It indicates whether the process in running as per norms or whether there is a potential flaw.
- According to the condition, it gives out electronic signals. If the signal is negative, workers will understand that there is a problem in the process.
- The machine stops, immediately of course, and the workers can stop the production until the flaw in the process is fixed.
- The main aim of Jidoka is to increase production quality. This is what standardization deals with.
- It involves developing strategies that adhere to perfection and quality.
- When a flaw is discovered, it is not only fixed, but efforts are also undertaken to see that it does not occur again, and the quality and standard of the same product are maximized.
The Jidoka Process
As seen in the figure above, without Jidoka, the defective piece continues to be produced and ejected. It is only after ejection that the worker may realize that the product is defective and then stop the process.
In this figure, with Jidoka, the Andon light glows brightly indicating that the product is defective. The process is halted immediately, and necessary steps are taken.
- This involves detecting the problem.
- The machine is fixed with the right components so that the abnormality is immediately identified.
- For this step, machines may be fixed with sensors, electrical cords, push buttons, electronic devices, or may be fed with proper instructions to identify if a product is defective.
- Once a defect has been spotted, the machine stops immediately.
- The machine is designed to stop on its own, no staff or worker needs physically stop it.
- The fact that a defect has been detected is indicated through signals. Once that is done, the staff might rush to the site to find out why the process has been halted.
- When the machine stops, the production line needs to be stopped.
- You might wonder why the entire line needs to be halted due to one or more defective pieces. This is done because there is a likelihood of defective parts or components to have been manufactured along with the defective part or component.
- To avoid this over-production and wastage of material and equipment, the production line is halted.
- After this, steps are undertaken to fix the problem. Sometimes, this may be a minor glitch, while at times, there may be a major problem.
- Once the error is fixed, the production resumes.
- The last and rather vital step of Jidoka is to investigate the source of the problem.
- You have to find out answers to the following questions: 'Why the defect has occurred?', 'What kind of defect is it?', 'How can it be fixed?', 'What can be done to prevent it?', and so on. Root-cause analysis tools are widely used to get to the bottom of the problem.
- Through this process, efforts are undertaken to find out the best solution for the defect, and to prevent it from occurring in the first place.
- As more and more investigation and research is being carried out, better methods of manufacturing are discovered, better problem-solving techniques are invented, and the product quality increases.
- Jidoka is mainly used in the manufacturing and automotive industries; however, it can be demonstrated in simple products used in daily life as well.
- For example, if your kitchen cabinet is fixed with a dustbin, you will notice that when you open the door of the cabinet, the lid of the dustbin is automatically lifted.
- This is because there is a string that helps lift the dustbin lid the moment the door is opened.
- Consider a printing press machine. If a sheet is missing in the machine, a sheet detector raises the print cylinder. This is due to Jidoka.
- In the manufacturing industry, a sensor is used to check if the components are in alignment. Even if a small part is out of alignment, the machine is stopped.
- Some high quality machines use the recall procedure. Sometimes, despite the best counter-measures, some products in the production line may slip through the machine cycle, undetected. The recall procedure checks every single product once again, before the final output ejection.
- Light curtains are used in automatic feed machines. They have a presence sensor that stops the machine if a component is broken or is defective.
Benefits of Jidoka
- It helps detect the problem as soon as possible.
- It increases the quality of the product by proper enhancement and standardization.
- It integrates machine power with human intelligence to produce error-free goods.
- It helps in proper utilization of labor since the process is automated, workers can spend their time performing more value-added services.
- There is less scope for errors in production, which substantially increases the rate of productivity and lowers costs.
- Improved customer satisfaction is an important advantage as well.
- Good products are manufactured in lesser time.
Jidoka is one of the strong pillars of TPS (Toyota Production System). It helps prevent defects in the manufacturing process, identifies defect areas, and devises solutions to see to it that the problem is corrected and the same defect does not occur again. Jidoka helps build 'quality' and has significantly improved the manufacturing process.