Just yesterday I did a short research about the most often lean terms searched on Google. And guess which is one of the top three most frequently searched terms? Poka Yoke! Though I was not surprised at all I would like to add a few words about Poka Yoke. And about what you might not know about Poka Yoke up to today.
Poka Yoke – And what we can learn from Toys
In many companies when talking about lean you will sooner or later talk about Poka Yoke and Poka Yoke solutions. I had to realize that not very much was based on a real understanding of the term. So let me try to explain it in my own words.
Not for no reason a typical visualization of the term are puzzles. The characteristic of a puzzle is to have only one state, in which all pieces fit together. Like it is with your product, isn’t it?
But there is one major difference.
Poka Yoke driven by Product Design
The real Poka Yoke is driven by design, not by the process. That means there is absolutely no other way in assembly two parts together. In today’s production I see tons of processes not protected by Poka Yoke.
For example, when assembling a cover to a part which is available in two colors. Red and green. There is no protection to not assemble the red cover on a part supposed to get a green cover. Oh, indeed there is, most of you would reply: “Don’t you see all the sensors hanging around? And by the way, we scan all parts twice before selling them to the customer”. And sure also the Mizusumashi helps to supply the red cover and not the green at the Point in time the part gets assembled.
That is the more modern expression of Poka Yoke and is driven by the process, not the product design.
Poka Yoke driven by Process Design
Whenever you have to prevent parts from being assembled incorrectly inside your production process, you failed in product design already. Ok, that is quite harsh from me to say, but that is what you should be aware of.
The real Poka Yoke is driven by product design and not the process.