What is Poka Yoke in Lean Manufacturing ? Poka Yoke Examples

What is Poka Yoke in lean Manufacturing ? Poka Yoke Examples


A system or procedure which prevents defects from happening was developed by Late Shigeo Shingo, a Japanese manufacturing engineer who also developed Toyota Production System.

Poka-Yoka came from Japanese words, 
Poka: Inadvertant errors
Yokeru: To prevent

Poka-Yoke is also called fail-safing or mistake proofing devices or techniques.
These devices are used either to prevent the special causes that result in defects, or to inexpensively inspect each item that is produced to determine whether it is acceptable or defective.

Poka-Yoke defined

• The ability to find mistakes at a glance is essential because, “The causes of defects lie in worker errors, and defects are the results of neglecting those errors. It follows that mistakes will not turn into defects if worker errors are discovered and eliminated beforehand.”
• “Defects arise because errors are made; the two have a cause-and-effect relationship. … Yet errors will not turn into defects if feedback and action take place at the error stage”.

Poka-Yoke examples

  • An airplane pilot may use a simple check list to make sure everything is ready before flying his airplane.
  • In many hotels, lights are automatically switched on or off after inserting a magnetic card for a particular room.
  • Anti-theft car alarm
  • Spell-checker in MS-Word
  • Tags attached to the garments in an apparel store, which ensures that they are not inadvertently taken out of store.
  • Before closing any document file in Microsoft office, we receive a message which asks whether we want to save a file or not.
  • Home Appliances -Microwave, Washing Machine- will not work until door is shut

Classification of Service Failures with Poka-Yoke Opportunities

Most of the errors caused while delivering services can be originated by service provider or servers and also by the customers. In services the customer is also part of service delivery system. A service is initiated by the customer. Various errors are classified as below in the table

poka yoke-types of error
poka yoke-types of error

Benefits of poka-yoke implementation
A typical feature of poka-yoke solutions is that they don’t let an error in a process happen. But that is just one of their advantages. Others include:

  • Less time spent on training workers;
  • Elimination of many operations related to quality control;
  • Unburdening of operators from repetitive operations;
  • Promotion of the work improvement-oriented approach and actions;
  • A reduced number of rejects;
  • Immediate action when a problem occurs;
  • 100% built-in quality control.

Sachin Thorat

Sachin is a B-TECH graduate in Mechanical Engineering from a reputed Engineering college. Currently, he is working in the sheet metal industry as a designer. Additionally, he has interested in Product Design, Animation, and Project design. He also likes to write articles related to the mechanical engineering field and tries to motivate other mechanical engineering students by his innovative project ideas, design, models and videos.

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