2 min read

By: Adebayo B. Olanrewaju 

Competition in business is constantly increasing. More than ever before, providing high quality products and services is the key to survival and growth in today’s marketplace. Whether it is in manufacturing, healthcare or service industries, companies need to keep striving to achieve zero defects. While zero defects sounds great, it seems almost impossible to achieve. 

The fact is mistakes happen and errors can occur in all type of processes. A machine operator or office worker may get distracted or forget to complete a task or a machine can break a tool and cause an error. Many companies rely on training and work instructions to prevent errors. Historical experience indicates that no matter how much training an operator receives or how well the process is documented, human error can still occur. 

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While application of standard work practices and operator training are valid methods for reducing the frequency of errors, they do not always prevent errors from occurring. Mistake Proofing also known as error proofing or Poka-Yoke methodologies can detect errors and prevent the non-conforming part from moving to the next stage of the process or leaving the facility. 

Furthermore, by implementing Error Proofing techniques to detect the error at the source, we can prevent the non-conforming part or product from being produced. Then we can say to be truly on the road towards zero defects.

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What is Mistake Proofing / Error Proofing?

Many practitioners consider the terms Mistake Proofing, Poka-Yoke and Error Proofing one and the same. Although the titles are different, the fundamental purpose of all three is to prevent errors that cause results into defects, the operator should be notified if an error has occurred so as to prevent the defect from moving to the next step in the process or reaching the customer. While they are the same in many ways, but investigating the history shows some slight differences between them.

  • Mistake Proofing and Poka-Yoke consist of three levels of application. 
  • True Error Proofing is made up of only one level, which is the equivalent of the highest level in Mistake Proofing or Poka-Yoke. 
  • Mistake Proofing is devoted to the implementation of devices or methods that prevent an error, provide notification of an error or prevent the defect from moving to the next step. 
  • Error Proofing is the act of implementing “fail-safe mechanisms” to prevent production of non-conforming parts – Error Proofing focuses on error prevention at the source or point of creation.
  • Poka-Yoke is very similar to Mistake Proofing except that it is centered on the human factor.
  • Poka-Yoke focuses on reducing or eliminating human error, which cause defects.

The heart of Poka-Yoke is more of a concept than a procedure. Therefore, implementation of Poka-Yoke is governed by what people think they can do to prevent errors in their workplace, and not by a set of step-by-step instructions on how they should do their job.

The Poka-Yoke philosophy is based upon two fundamental observations about human behaviour: 

  • Mistakes are inevitable.
  • Errors can be eliminated.

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About the Author

Adebayo is a thought leader in continuous process improvement and manufacturing excellence. He is a Certified Six Sigma Master Black Belt (CSSMBB) Professional and Management Systems Lead Auditor (ISO 9001, 45001, ISO 22000/FSSC 22000 etc.) with strong experience leading various continuous improvement initiative in top manufacturing organizations. 

You can reach him here.

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