Poka Yoke: Errors Prevention Strategy

Poka Yoke

Human error is an inseparable part of any process that involves manual work. While human errors adjust pretty well in most cases, the manufacturing industry differs. Mistakes in manufacturing because of humans can lead to defective products.

Anyone can make a mistake, and it is pretty natural. However, you can save yourself a lot of trouble during manufacturing if you can catch these mistakes timely. The tendency of errors is virtually limitless; for instance, you could shrink a pair of jeans by mistake. That’s not a huge deal, but a measurement mistake in the manufacturing world can also cost the company its reputation and a considerable amount of money.

Therefore, companies must avoid situations like these by using a checking method. For instance, a writer would install a “spellcheck” to catch writing mistakes or a person who washes his clothes with cold water to prevent them from shrinking.

It is precisely what the Poka-Yoke technique does-but in manufacturing. The method prevents issues before they arrive and is straightforward yet powerful.

What is Poka-Yoke?

Poka-Yoke is a relatively different concept that doesn’t focus on perfection in processes but accepts the inevitability of errors in human-run processes. The method provides a basic framework that can help minimize mistakes.

The simplest way to explain it is to think of it as a technique for consistent improvement, which falls under the umbrella term of Lean Management. The method mainly helps reduce the chances of making mistakes. It also simplifies any industrial process and adds more structure to it.
There’s a chance that if you are from the manufacturing industry or any other commercial setting, you have come across analysis paralysis- where you don’t know how to analyze a particular issue.

This way, the professionals have a clear vision about the direction they should move in if there’s a problem. Simply put, the Poka-Yoke is a method used for early error detection.

The Origins of Poka-Yoke

Poka-Yoke was first called ‘Baka Yoke,’ which means ‘idiot-proofing.’ However, the term was slightly changed because no one enjoys being called an idiot. The current version of the phrase “Poka-Yoke” is less offensive and translates to ‘mistake-proofing.’

The term was first coined by Shigeo Shingo, who worked at Toyota as an industrial engineer — he was responsible for proofing and safety checkups, also called Lean.

As per the records, he noticed that the workers in the factory were responsible for adding a switch during the manufacturing process, and they didn’t insert the spring under one of the buttons. To resolve this issue, he had to restructure the whole thing and ensure no mistakes.

The workers had to prepare the springs and add them to a placeholder, followed by adding the springs from the placeholder to the switch as required. If the workers forget to install the spring, they could easily see it in the placeholder and fix their mistakes.

Poka-Yoke Technique: When you should use it

The Poka-Yoke technique started in the car manufacturing industry, but has now been adopted by many others worldwide. Today, almost every manufacturing industry uses the method, mainly because of its effectiveness and usage.

Contact Approach

The contact approach is the simplest version of the Poka-Yoke technique, where a person might see an error visually. For instance, a company adds a quality assurance section to a factory conveyor belt or hires a proofreader to check the work before sharing it with the client. There are several other physical methods that you can use in this regard. For instance, you could add a physical check for a piece of machine fitting a specific section in the design in one way. This approach is called a ‘control’ type in the Poka-Yoke.’

 Constant Number

The constant number approach focuses on the number of steps involved in the manufacture. This way, you can get an alert if there’s a miss on any of the steps.

For example, many car manufacturing companies install an indicator for a seat belt if it isn’t fastened correctly. In professional manufacture, it is also called the ‘warning’ type of Poka-as it focuses on the mistakes that a person may have made instead of stopping the process from the get-go.

Performance Sequence
The performance sequence focuses on the order of the manufacturing process. For example, a dishwasher won’ start working until the door is closed off properly. This approach is called the ‘shutout’ or ‘shutdown.’ The performance sequence is a fool-proof method as it ensures your manufacturing processes are Poka-Yoke, preventing an error. In this scenario, mistakes are nearly impossible.

Examples of Poka-Yoke Technique from Real-Life

Essentially, Poka Yoke is a preventive process that provides manufacturing companies with more protection against errors. It stops them from working in case there’s a process error. Here are three real-world examples to help you picture this in action.

1. Car Safety
The automobile industry is one of the most common places where the Poka-Yoke technique is used. The cars have various systems, such as seat belt detection, that tell the drivers if they don’t fasten their seat belts.

Similarly, some sensors alert the drivers if there’s a nearby object or the car drifts away to the center of the road. Moreover, the automatic vehicles that require drivers to shift the gear manually before driving the car off are also an example of the Poka-Yoke process.

2. Trains, Microwaves, and Washing Machines
Microwaves, washing machines, and microwaves are now a big part of our lives. However, all these devices don’t work until their doors are open and available. It’s an essential and crucial step that ensures that machines operate as they should.

3. Spell Checks
Many software, such as MS Word, highlight potential grammatical and other mistakes in the text to alert the writer/readers. This way, the users can prevent embarrassing situations before sending off this text.

The Poka-Yoke technique is a remarkable approach to minimizing design, function, and efficiency issues. It primarily belongs to the manufacturing industry, but many others now use it for their needs. You can find examples of the Poka Yoke technique worldwide, making it ideal for almost every industry.

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