Expanding the Meaning of Poka Yoke in Lean Manufacturing
What’s in our name? Quite a bit actually.
Poka yoke (or poka-yoke, but not poke yoke), translated from the original Japanese, means to “avoid mistakes”. We certainly strive for that in manufacturing, oftentimes in life generally too.
You're likely familiar with the term and its basic application. Make no mistake (pun intended), there are plenty of great ways to use fixtures or programmed ways to apply poka yoke techniques that can make a real difference.
If poka yoke is new to you, it’s interesting to explore the source material from Shigeo Shingo, who is considered to be a significant contributor to the concepts of the Toyota Production System and lean thinking. If you’re interested in reading more, I recommend:
- Zero Quality Control: Source Inspection and the Poka-Yoke System by Shigeo Shingo
- A Study of the Toyota Production System: From an Industrial Engineering Viewpoint by Shigeo Shingo and Andrew P. Dillon.
What is Poka Yoke?
The concept is directed at stopping a defect or incorrect action at the time and place of occurrence and fixing it forever. You’ll find hundreds of examples of this from driving your car to medical practices to fixtures in assembly operations, to name a few. A familiar example is that with many vehicles, you can’t start the car unless your foot is on the brake - it’s designed to prevent the error of starting the car and rolling off with no control.
Poka Yoke - Not Just About Machines
I’d like to spin the concept a bit in order to think about poka yoke as a method for improving performance overall, rather than by fixing specific defects - you know, looking at the forest rather than individual trees. It’s not too far from the Japanese meaning, but it makes me think about it in a more proactive way.
Shingo’s framework identifies five elements that comprise production: What, Who, How, Where, When and Why (5W1H). He includes machines and workers in his definition of Who. Initially, poka yoke had more to do with the machines - creating assembly fixtures that were error-proof, counters, and other similar fixes that dealt with specific issues and were tied more to the process or machine.
I’d rather think about the workers.
If we think about poka yoke as a way to essentially “error-proof” our workforce, we can certainly amplify the benefits.
A Poka Yoke Production Example
An example might be helpful. I was in a plant a few years ago where they had the opportunity, near the end of a fiscal period, to satisfy customer demand and meet production objectives that would impact employees’ bonus opportunities.
To secure those bonuses, it was necessary to ramp up production during the night shifts, which had less staff and therefore lower production capability. So for a two-week period, they reassigned a group of experienced operators and supervisors to the night shift. In the end, they made the numbers for the period, satisfied the customer demand and got the bonus.
What was most interesting to me was that the performance numbers set a productivity record several points higher for all shifts during the period.
When I asked the production director what was the main reason for the significant performance improvement, he said the biggest factor was having experienced people guiding processes. They knew how to quickly identify and resolve issues and had the knowledge to anticipate where snags would occur, staying ahead of stoppages.
Mistake-Proofing Your Workforce Through Know-How
It would be easy to say, “just keep doing that”, and have experienced people added to each shift. But that’s often not financially feasible.
So what can be done instead? If we use a traditional poka yoke approach, we’d identify the issue - let’s say downtime in a certain area, or safety issues in another - find a solution that fixes the specific problem, then move on to the next one.
But if we take a more people-focused poka yoke approach, we’d instead find the best performers in the organization on those problem issues. We’d ask them specifics about what they do and how they achieve those superior results - then ensure that the detailed wisdom is added to the work instructions and is consistently made available to the problem areas. The most important thing in this scenario is the knowledge transfer and establishing a mechanism to make that happen, oftentimes using Poka’s Connected Worker solution. It balances the strengths of the people across the organization and raises the overall performance level.
What’s In Our name?
The original vision of Poka Inc., has remained the same: improve frontline worker performance through the sharing of knowledge, making it easily available when and where it’s needed.
Co-founder and Poka CEO Alex LeClerc said that in his family’s multi-plant business he saw that the “best mechanic in one plant resolved issues quickly and avoided problems that were not handled well in other plants. Working in silos, versus a network, was not effective. A factory is like a chain - only as strong as the weakest link.”
The impact of that observation was significant. Alex added, “In many of today’s high-volume, fast-paced and automated production processes, a small error or short stoppage has a big impact and high cost.”
In this instance, the knowledge and performance resided with one person. The challenge was to recreate the problem-solving environment and insights at other plants to bring them all up to the same level.
In the early stages of Poka’s development, the vision remained steady but a name was needed. Co-founder Antoine Bisson came up with the name that fits like a glove: Poka.
Short, snappy, with a bit of a ring to it, but, most importantly, it expresses in a word the mission of the app: Mistake proof (poka yoke) your workforce by actively seeking, then consistently sharing, knowledge.
Bill Blank is an implementation specialist on Poka's Professional Services team. He has a broad background across various company functions and loves manufacturing. He thrives on meeting people in the field and helping them make transformations with Poka.