Mistake Proofing / Poke Yoke

What is Poke Yoke

Poke Yoke is Japanese for mistake proofing

It refers to any inexpensive mechanism - that prevents the operator from doing an error

So its waste elimination directed mostly at removing human error either by removing the cause or by eliminating the chance of error by stopping the process

Carpenter Craving in Wood

When to use Poke Yoke

  • To reduce / prevent human errors any where

  • To reduce risks of human error occurrence in your FMEA

Rules for Mistake Proofing

  • should be inexpensive

  • Common sense based - by the actual doer ( all of us have heard the story of using a fan to detect empty soap cartons from the packaging line)

  • Remove error from source ( for occurrence based )

  • Make the error visible ( if detection is required ) eg. unless you click accept terms and conditions, you can't proceed with registration on various sites

Crossing Sign

How to do Mistake Proofing , Poke Yoke

  • It's a lean tool - so do it with "doers", on the floor or at-least after observing the process 

  • If you have done a FMEA for your process - look for areas, where an error is occurring due to human, and you want to reduce the occurrence of the error

  • If no FMEA than - look for processing accuracy data and find steps that can be error-proofed, again based on inadvertent human error

  • Once you have selected the target area - come up with a technique that may work, is in your control to deploy and deploy quickly

  • Observe for a period, if it works, deploy in a larger area 

  • Here are the steps 

    • Step 1: Identify problems - Source: Brainstorming, FMEA, reports...

    • Step 2: Prioritize Problems - Use Pareto, FMEA RPN

    • Step 3: Seek out the root cause - Do NOT use Poke- Yoke to cover up problems or treat symptoms - Do brainstorming, 5 whys, Fishbone, data analysis

    • Step 4: Create solutions - make it impossible to do it wrong

    • Step 5: Implement and measure the results - Learn from them and implement in a wider area

Examples of Poke Yoke / Mistake Proofing

  • You cough/ sneeze to throw out foreign bodies entering your body - Nature's mistake proofing

  • 2 wheeler with button start, won't start until you have the handbrake applied 

  • When making an online payment from your cards, the system won't let you proceed if you put less than the required number of digits.