Mistake Proofing: Poka-Yoke

Mistake Proofing Poka-Yoke Achieving Perfection

Every methodology is imperfect until it is made perfect with the use of various tools and techniques. Achieving perfection is a never-ending process and by perfection we mean ‘zero defects.’ It is human behavior to make mistakes and in order to prevent those mistakes Shigeo Shingo adopted the poka-yoke technique in the Toyota Production System (TPS).

The term poka-yoke is derived from Japanese, which means ‘mistake proofing.’  In Lean Six Sigma, it is another helpful tool, which is used for continuous improvement.

Types of poka-yoke can include:

Defect Detection – The objective of adapting the poka-yoke technique is to eliminate any errors or mistakes, and to ensure that its recurrence is eradicated once and for all.

Defect Prevention – This is a technique which warns users about the occurrence of an error and predicts the possibility of a defect.  This capability of a poka-yoke mechanism is very effective because a corrective action is implemented as soon as the error is detected and it doesn’t allow such errors to pass on to the next process.

A classic example of a poka-yoke device is electric sockets. The sockets are shaped in such a manner that when they are plugged in, it goes the right way. So, the question of making a mistake is ruled out in this case.

Having an error-free system is great and it has some additional benefits as well, such as:

  1. In Lean manufacturing, poka-yoke ensures that there is an absolute reduction in the number of defects, which would result in the production of high quality items.
  2. Eventually, safety measures are enhanced as there is a reduction in the rate of errors.
  3. There is improvement in the production process because of the non-value added element or waste removal.
  4. Poka-yoke devices are inexpensive and easy to implement.
  5. The ultimate advantage of installing these devices is the improvement in customer satisfaction through improved quality and delivery performance.