Comments on: The Two Directions of Poka Yoke

By: Stephanie Rea

Stephanie Rea — Fri, 10 May 2024 09:01:47 +0000

Poka Yoke can take two different approaches to remove defects. Whether it permits only a one-way possibility or allows for different actions without causing a defect. It is interesting to see that Poka Yoke is not only used in manufacturing but can be applied to our daily lives. It allows individuals to better understand the benefits of implementing this tool and and how it reduces defects. When putting a SIM card the defect will not occur because there is only one way where it will work. Companies can benefit from implementing this tool because it can prevent defects or at least make them so obvious that they are dealt with.

By: Taner Kuzu

Taner Kuzu — Sat, 09 Mar 2024 10:51:22 +0000

Hi Christoph,
Your studies and blogs have many great observations and directions for all lean-enthusiastic engineers and leaders. Lean is now global word for Toyota manufacturing systems almost more than a quarter century but there are still a lot to learn from Japanese culture and Toyota practices literally.
Poka yoke is another one. I do prefer use Japanese words in business while I am applying becasue it is deeply linked with its motherland root somehow. Passion for journey in excelence is kind of a Toyota culture. Poka yoke is tool for reaching zero defect. But again like all other lean mechanism, it has to be worked in harmony with many other little lean tools/meachanism to be more effective.
Poka yoke itself needs these tools primarily. Such as; jikotei kanketsu, hatsumono-owarimono.
Simply saying, jikotei kanketsu is not to accept, not to produce, not to transfer the defects in one process which is fully supportive for poka yoke. It also configures where and how to install poka yoke in the process flow. Once you have jikotei kanketsu study for whole process flow thus you know where to structure defect-trap (poka yoke).
Second point is that hatsumono-owarimono which is shift-end or shift-beginning control points for product and process CTQ points. You should also check poka yoke applications are functional or not effectively, otherwise you will have leakage which ends up with high scrap or big complaints later on.
Poka yoke is a concept and mind-set for each shop-floor member to follow and monitor the process, not something that you install and forget.
Thank you so much for raising this crucial lean tool!

By: Christoph Roser

Christoph Roser — Sat, 09 Mar 2024 08:50:07 +0000

hello Hugh, great example on how NOT to do it. Glad it is fixed now 🙂

By: Hugh Alley

Hugh Alley — Sat, 09 Mar 2024 06:23:57 +0000

In Vancouver, Canada, thé local transit authority had transit users suffer through several unfortunate years when their passes could be entered into the readers in one of four different orientations (rectangular cards that required a specific face up and the stripe on a specific side) but only one worked. It slowed the bus loading process by 15-30 seconds per passenger, on average, which became a significant factor in busses running late. This was only fixed when they replaced the entire system, changing the type of fare card and using proximity readers where the orientation didn’t matter. I gritted my teeth every time I boarded a bus.

By: Christoph Roser

Christoph Roser — Thu, 07 Mar 2024 10:49:00 +0000

Hello Andrey, excellent example. Toyota relays can be put in only one way, GM in any way. In this case, I think I prefer GM.

By: Andrey A

Andrey A — Wed, 06 Mar 2024 17:23:02 +0000

Most people who did their own car maintenance heard about relays. A relay is an electric switch that closes or opens a circuit using a solenoid. a typical 4 pin relay will have two main power pins and two signal pins. In the late 90s and early 00s, Japanese manufacturers keyed individual relays so that each one would only go into one slot in the fuse block even if the pin layout was otherwise identical.

Sounds great until you are working on older car and a relay with a matching key isn’t readily available. a lot of the times, it’s not possible to just swap a suspect relay with a different from from a less essential function for testing. Sometimes I joke with customers that their horn is actually a built in bench tester for fuses and relays. If you press on the center of your steering wheel and gear a loud noise, the relay is good and the fuse is good!

here’s one example of keyed Toyota/Lexus relays.

https://www.ebay.com/itm/355122125418?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=qQjV5OYPQ9W&sssrc=4429486&ssuid=hjGDds4bTsS&var=&widget_ver=artemis&media=COPY

notice how they have different colors and key notches.

GM, on the other hand, took a much better approach and made a lot of their 4pin relays work no matter what orientation it was inserted in.

ACDelco GM Original Equipment 13500114 Multi Purpose Relay https://www.amazon.com/dp/B08NMVWKCS?starsLeft=1&ref_=cm_sw_r_apan_dp_WSB62CS1JAP66C2JHXH8_2

if you look up the electrical diagram. main power pins are on opposite corners. same with the signal pins. if you were to crack one open, you’d see the solenoid plunger plus a contact on both sides and the main circuit will close regardless of signal polarity.

By: Jana

Jana — Wed, 06 Mar 2024 07:53:49 +0000

Great read! It’s cool how Poka Yoke isn’t just a factory thing but also sneaks into everyday life to stop us from messing up. I never thought about it in terms of letting us do different things without goofing up versus just allowing the right moves. Makes you think twice about how stuff’s designed, huh? Thanks for sharing!

By: Christoph Roser

Christoph Roser — Tue, 05 Mar 2024 13:45:56 +0000

Hi Steve, good take on the different ways to avoid defects. I agree with your preference 🙂