I’m relatively new to Lean Six Sigma terminologies and when I first heard someone refer to a “poka yoke,” I thought, “hmm… that must be a new dance move.”
I quickly learned that a poka yoke is not a new way to get funky on the dance floor—but rather a term coined by Japanese industrial process engineer Shigeo Shingo to refer to methods that can be used to “mistake-proof” a process.
Keeping your manufacturing process free of any errors is an important thing to think about as you begin your quality improvement initiative. In fact, if your goal is to completely eliminate defects in your product or process, thinking about how you can prevent both human and mechanical mistakes from occurring is a good place to start.
While error-proofing can also be accomplished with automation and computers, poka yokes were originally developed as a mechanism to prevent errors in small operations and were only composed of simple, inexpensive, and quick fixes. For a poka yoke, the costs of time and equipment shouldn’t be more than the estimated savings of eliminating the defect.
Right now you're probably using a computer that has a built-in, very simple poka yoke: the plugs for the printer, monitor, etc. only fit into designated outlets with corresponding plug shapes. You can try all you want to jam the printer cable into the outlet designated for the speakers, but you won’t be able to! Installing warning bells or flashing lights to alert a worker that a machine is malfunctioning is an example of a poka yoke that detects, rather than prevents, defects.
Steps and Tips for Applying a Poka Yoke
1. Create a process map to help you understand and communicate all the activities in your process. This will make it easier for you to catch possible errors in your current process and plot where you think there might be an opportunity to employ a poka yoke.
2. Make a fishbone diagram to help you brainstorm potential causes of a problem you may have noticed while creating your process map.
3. Decide what kind of poka yoke you’re going to implement. Ask yourself: Do I want to completely prevent a defect from occurring, or do I just want to highlight that an error has occurred?
4. Test your poka yoke.
5. If it’s successful, implement the poka yoke. Train workers and track your savings.
Poka Yoke’s in My Life
- I travel quite a bit, and I noticed that I was constantly forgetting to pack my cell phone charger. To keep myself from forgetting, I bought duplicate chargers and placed them in each suitcase I might choose to take, as well as in my car. Unfortunately, this poka yoke can’t keep me from leaving my charger at my destination and forgetting to pack it back up again when I’m leaving to come home!
- I place lists and sticky notes everywhere to remind me of grocery store items that need to be bought or household chores that need to be completed. I also keep tasks and deadlines on sticky notes at work to keep me organized.
- My all-time favorite and most-used poka yoke is my computer’s spell checker. I can’t think of a better example of a poka yoke that prevents more errors from occurring than this one!
What are examples of poka yokes you’ve used either in your personal life or at work?
Image licensed under Creative Commons Attribution ShareAlike 2.0.