For the past few weeks, I have been working on a project where I learn automotive processes in order to document standard work so that each activity is precisely described by motion, time, task sequence, and minimum inventory required to conduct the activity. The only problem is that I have never worked on an automotive process and I don’t know that much about automobiles in general – except how to drive them and pump gas into them. This lack of knowledge, however, made learning the process very enjoyable because I was able to review the process with an open-mind and apply Lean Six Sigma methods to document improvement opportunities.
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For the first few days of this project, my daily standard work was to shadow different departments and lines in the automotive plant in order to learn their processes and parts. However, this method made it very difficult for me to “truly learn” the process and its flow since I wasn’t actually doing the work. Because of my way of learning, I asked if I can be put on the line as a new hire and by the middle of the week, I was “hired” as a new line employee in sub-assembly.
There has never been a time where I have felt the power of poka-yoke more than when working at this plant. Poka-yoke (in Japanese, poka means error and yokeru means to avoid) is a term that means to mistake proof a process by building safeguards into the system that avoid or immediately find errors – basically, stopping me from assembling incorrect parts or making assembly errors. And believe me, I made errors!
Thankfully, none of these errors were passed down the line because:
- the machine in the cell would not start until all parts needed for assembly were placed in the machine, in the correct location,
- the machine in the cell would not start until each part placed in the machine was of perfect quality and inserted properly, and
- an indicator light would turn red if the final assembled part (after the machine assembly) had a quality issue, indicating the employee in the cell to not pass this part down the line.
Placing these poka-yokes into the system enabled the process to flow smoothly and without defect. It built quality at the source which not only gave each employee (especially me!) trust in the part and assembly process they were working on, but also reduced the cost of poor quality and customer incidents that could have stemmed from even a small scratch on a part.
Written by Ana Bailey, Lean Deployment Specialist at LeanCor
Related articles
- Poka Yoke – or – foolproof system (hrhead.wordpress.com)
- The 5 Whys: Brilliant Processes Drive Brilliant Results (leanlogisticsblog.leancor.com)
- Toyota’s People System (bobsleanlearning.wordpress.com)
The Lean Logistics Blog 
Ana,
I enjoyed reading about your discovering Poke Yoke or Error Proofing devices and strategy. Doing the work is often overlooked as a way to reveal the possiblities to improve an operation. As a suggestion, you might look at how to apply poke yoke in logistics or warehouse operations. Pick to Light and visual aids are helpful but not truely error proofing. How to prevent mispicks, missorts, typos, etc. is a challenge in the modern warehouse environment.
One aspect of a vigorous robust operation is predictabilty. If you would allow me to further suggest, try looking at operations with the eye to what could go wrong as opposed to what is going correctly.
Thank you, Dan