What is Poka Yoke?

Poka Yoke: What's it all about?
6 min read

The term poka yoke may sound odd to the average person reading in English, but it is actually a very popular and helpful concept. The term comes from the Japanese language where it was first developed. It is roughly translated to mean mistake-proofing and was first used as a manufacturing idea by the Toyota Motor Company.

The ideas behind poka yoke are used in many ways throughout the world and help to make things a lot safer. They are also used within manufacturing, warehousing, and other facilities to reduce or eliminate the risk of mistakes from occurring. When implemented properly, poka yoke can really help to benefit an organization, the employees, and the end users of any product.

History of the Term Poka Yoke

What is now known as poka yoke was originally called baka yoke. Baka yoke, however, is translated to fool proofing, or even more accurately, idiot proofing. While the concept is the same, the insulting meaning behind baka yoke was dropped in favor of the less offensive poka yoke.

History of the Concepts Behind Poka Yoke

In the 1960’s the term poka yoke was first applied to the industrial process by Shigeo Shingo at the Toyota Motor Company. At the time, factory workers who were putting together a small switch would often forget to insert a spring under one of the buttons, which would obviously cause issues later in the production of the vehicle.

To help prevent this from happening, a new process was created where the workers would start by placing the two springs that were needed for this part into placeholders. They would then assemble the switch like normal. If, however, after completing the process they saw that one spring was still there, they would know instantly that they forgot to install it. They could then take the spring and put it in the proper place before moving the completed switch to the next steps.

Shingo realized that humans will always make mistakes. It is not effective to simply provide training, or even discipline, to try to prevent these types of mistakes since it is impossible to eliminate the errors in this way. Instead, he came up with the concept of poka yoke in order to have a system in place that would help to overcome the natural tendency of humans to make these types of errors.

Of course, over the coming years many other processes were added or updated in order to prevent common mistakes. Over time, the Toyota Motor Company was able to dramatically improve the overall quality of their products and reduce the number of defects. Not only that, but they were able to accomplish these goals without significantly extending production time, quality control expenses, or other issues commonly associated with error prevention.

Benefits of Implementing Poka Yoke

The benefits of poka yoke in manufacturing are quite extensive. When implemented properly, it can help to eliminate many common defects in products. In addition, it can help to improve the overall safety of the facility and the productivity of workers. Any company that is thinking about implementing poka yoke strategies into their organization should look closely at the various benefits that it can provide, including the following:

  • Reduced Training – When a process is put in place that prevents errors from happening, there is no need to train employees on how to avoid that error.
  • Less Need for Quality Control – Quality control teams often have to check for common errors. When the errors are eliminated due to a poka yoke process, this will no longer be necessary.
  • Eliminating Defects – When a customer purchases a product that has a defect, they are often very upset. This process can be very costly and may even result in a lost long-term customer. Since many defects can be eliminated through poka yoke, the savings can be immense.
  • Immediate Action – Poka yoke can often make it possible to identify mistakes as soon as they happen so they can be addressed rather than discovering them down the line.
  • Improved Profits – Any organization that is able to reduce the time and effort required to correct defects will find that they are able to improve profits on each product significantly.
  • Safety Improvements – Mistakes and defects often cause safety hazards. These hazards can be prevented by implementing processes that eliminate the risk of mistakes.
  • End User Satisfaction – Customers are happier with built in protections such as the ones listed below. This will make them more likely to become repeat buyers.

The specific benefits of poka yoke, and how beneficial they are, will vary significantly from company to company. Taking the time to look for common mistakes or potential errors that occur and implementing a process to prevent it or address it right away will always be a good idea.

There may be many other benefits beyond those that are listed here. Each organization will want to look at the way things operate currently, and then how things run after poka yoke inspired steps are implemented. The benefits will typically be easy to see and long lasting, which is exactly what organizations will want whenever implementing any type of system like this.

Examples of Poka Yoke in Everyday Life

One of the easiest ways to really understand what poka yoke is and how it can be beneficial is to look at some of the ways it is used in everyday life. The following are some examples of mistake proofing ideas or designs that people interact with all the time:

  • Safety Clips on Treadmills – Modern treadmills have a clip that attaches to the user and then plugs into the machine. If the person using the machine falls or gets to far back, it will unplug the clip and stop the motor, which will help to prevent or minimize injury.
  • Doors on Elevators – Doors on elevators have sensors to detect the presence of anything between them when closing. This prevents the doors from fully closing or the elevator from moving when something is in the way.
  • Spell Check – Spell check is a type of poka yoke that many people use every day. Commonly misspelled words are automatically detected and sometimes even corrected to avoid mistakes.
  • Brake Assist on Cars – Modern cars are equipped with a brake assist feature, which will apply the brakes if the car detects an object that it will otherwise hit. This system can help to prevent (or at least reduce the severity of) a crash if the driver does not react quickly enough.
  • Size and Shape of Electrical Plugs – The prongs on electrical plugs typically only fit into the outlet in the correct way, which prevents the device being plugged in from getting incorrect electrical flow.
  • Flight Captain Meals – This example may seem unusual, but it is very effective. The captain of a commercial airflight gets a meal that was prepared separately than everyone else. This way, if either the main meal or the captain’s meal is contaminated, someone will still be able to fly the plane safely.
  • Queue Management Systems – Whether it is lines at grocery stores or lines for a ride at an amusement park, queue management systems help to prevent many problems including disputes between customers.
  • Water Detection – The presence of water in many systems is a hazard that can cause serious (and costly) problems. Water detection sensors that can shut down a system will often dramatically reduce the repair costs.

There are thousands of examples of poka yoke that people interact with on a regular basis. Whether you are working in manufacturing where a lockout tagout system is followed (a life saving example of poka yoke) or you are at home relaxing, this concept is helping to keep people safe everywhere.

Looking for Poka Yoke Opportunities in Your Facility

Now that you have a good understanding of what poka yoke is and how it works, you may want to start implementing it into your organization. One of the great things about the concept of poka yoke is that it does not necessarily require a huge overhaul to how an organization operates. Instead, every individual process can be adjusted and improved individually, if needed, to get the benefits that poka yoke offers.

While it can sometimes be difficult for a department manager to get buy in from all the other teams, for example, a poka yoke inspired improvement in his own department can be added right away. By finding areas that have the potential for mistakes, and then putting processes in place to prevent them, even a single person in a company can get great results.

Over time, the organization will notice that the department or departments that are using poka yoke strategies are producing better results with fewer mistakes. They will then likely want to expand the use of the poka yoke methodologies quickly.

Of course, it is always better to get teams throughout the organization to buy into the poka yoke processes together. This will allow the company to enjoy the benefits much more quickly than would otherwise be possible.

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