The Foundation of Mistake Proofing / Poka-Yoke
Providing high quality products and services remains the key to survival and growth in today’s ever competitive 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 any type of business or manufacturing process. A machine operator or office executive 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.
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 proves to be a viable technique that can help detect errors and prevent non-conforming parts or products from moving to the next stage of the process or leaving the facility. By implementing Error Proofing techniques to detect error at the source, we can prevent non-conforming part or product from being produced.
What is Poka Yoke?
Poka-Yoke is Lean concept gotten from the Japanese word (ポカヨケ) which means “mistake-proofing.” It was first introduced in the 1960s by Shigeo Shingo. This powerful techniques are being used today to error-proof processes, products and services to stop them from going defective. Poka-Yoke has a primary goal of eliminating defects and mistakes by designing systems in a way that they cannot be made wrong. That is, to design processes with safeguards so that errors would either be immediately discovered as they are about to happen or simply prevent them from occurring in the first place.
Categories of Poka-Yoke Techniques
Error-proofing techniques can be categorized into three (3) levels, namely:
- Prevention: In this type of Poka Yoke, mistakes are prevented from occurrence. An example of this may be putting a guide over a button so it cannot be pressed accidentally.
- Detection: This type signals when a mistake has just been made and alerts the operator so that the mistake can be quickly corrected. An example of this would be using tags that are coloured-coded to identify which process step a product is in.
- Correction: This type automatically corrects the mistake as they occur. An example of this type of Poka-Yoke is a barcode scanner that automatically enters the correct product information into a computer system.
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.
Examples of Poka-Yoke
- Using colour-coded tools and equipment so that the operator can easily identify the correct tool for the job and avoid using the wrong one.
- Using positive and negative feedback mechanisms such as designing a machine to stop working if it detects an error, thus preventing the product from being further damaged.
- Using sensors on a machine to detect when something goes wrong and automatically shut the machine down.
- Using mechanical devices or physical barriers to prevent mistakes from happening by preventing people from getting too close and getting hurt.
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Conclusion
Poka-Yoke can be applied in any process where human error may occur not just in manufacturing. It is all about designing systems in a way that prevents, detect or correct a mistakes or error. Poka-Yoke techniques can be quite simple and inexpensive, requiring minimal cost to implement and can help you achieve higher quality, lower costs, and increased customer satisfaction.
Considering Poke-Yoke and mistake-proofing your processes will go a long way in preventing things from simply going to go wrong. Murphy’s Law states that “Whatever can go wrong will go wrong”. With that adage in mind we do well to design tools, processes, products and services in the right way, with Poke-Yoke to stop things from going wrong, in order to prevent costly business mistakes.
About the Author
Olanrewaju, Adebayo Bamidele is a Lead Auditor of ISO 9001, FSSC 22000 / ISO 22000, 14001 & 45001 Management Systems, Certified Six Sigma Master Black Belt (CSSMBB), process engineer, and quality management professional with strong working experience and proven skills in manufacturing excellence, ISO management systems implementation, lean / digital manufacturing, and project management.
Adebayo is a Corporate Member of American Institute of Chemical Engineers (AIChE), Associate Member, the Institution of Chemical Engineers (IChemE), Corporate Member, Nigerian Society of Engineers (NSE), Corporate Member, Nigerian Society of Chemical Engineers (NSChE), Associate Member, Nigerian Institute of Management (NIM), and Associate Member, Institute of Strategic Management of Nigeria (ISMN).
He is an author of over 15 books and has published over 45 online courses on various e-learning platforms including Udemy, Alison, Learnformula & Study Plex.
You can reach him, here.
