Poka Yoke

Happy Easter everyone! Please egg-scuse the pun – but what a great opportunity to blog about Poka Yoke.

Happy Easter

Poka Yoke is a Japanese term for error proofing. This is key whether designing a new process or improving an existing one. Poka Yoke devices are often simple and inexpensive, sometimes we don’t even notice they are there, but they prevent mistakes, defects, accidents and injuries, and that’s no joke!

The principle was developed by Shigeo Shingo, to support the achievement of zero defects either by making it impossible to make a mistake, or by detecting defects as they occur and preventing them from going any further.

The shape and design of fuel pumps is an example of Poka Yoke  – the pumps for unleaded and diesel are different colours so the driver knows which is which, and if the driver does happen to select the wrong one, the nozzle of the diesel pump is too big to fit into the petrol vehicle, thus preventing misfuelling.

The flavour of the Nintendo Switch games cartridge is another example. – the cartridges, which are about the same size as an SD card, have been given a “horrendously bitter” taste by Nintendo, to discourage children from putting them in their mouths. (Thanks to a recent delegate from a Green Belt training course who licked his game card and confirmed this to be correct!)

To return to our Easter theme, one of my favourite Poka Yoke devices is used in Willy Wonka’s Chocolate Factory to error-proof his ‘Golden Egg’ process. This is known as the Eggdicator.

Willy Wonka eggdicator

When a Golden Goose has laid an egg it is automatically passed through the Eggdicator which determines if the Egg is good or bad. If the egg is good it is shined up and shipped out. If it is bad, a trap door opens and the egg disappears into the garbage. In case you are wondering, this is a true Poka Yoke device and not an inspection step – Wonka advises that the Geese are temperamental, hence the eggs pass straight down a chute and onto the eggidcator as soon as they’re laid, to eliminate the potential for the Goose to attack the Oompa Loompa when he eggstracts (sorry) the egg from underneath.  An educated eggdicator indeed!

Our challenge in process improvement work is to apply this thinking to the way the work gets done. How can we make it easier for people to get it right than it is to get it wrong? And when you do, the results can be cracking.

Happy Easter from all the good eggs at Catalyst.