Quality Improving Tool POKA-YOKE

In today’s competitive world any organisation has to manufacture high quality, defect free products at optimum cost. The new culture of total quality management, total productive management in the manufacturing as well as service sector gave birth to new ways to improve quality of products. By using various tools of TQM like KAIZEN, 6 sigma , JIT, JIDCO , POKA YOKE, FMS etc. organisation is intended to develop quality culture. The paper is intended to focus basic concept of poka yoke, types of poka yoke system, ways to achieve simple poka yoke mechanism. It also covers practical study work done by various researcher . In the recent years intensifying competition in the international economy caused a major change in approach to quality management.

The quality action should therefore include its reach the whole product life cycle, starting from customer identification requirements and expectations, by the customer’s service. The organizations by focusing on quality process approach should improve the existing quality management system, the defined processes and also their products by implementing the available philosophy (Kaizen, TQM, Zero quality defects), rules quality tools and methods of quality management “Process approach” to management of organization is a field developing dynamically. This concept is very universal , it works for all companies, because it integrates in transparent way all key mechanisms which result from requirements for quality management system and quality processes.


Poka-Yoke is a Japanese improvement strategy for mistake-proofing to prevent defects (or nonconformities) from arising during production processes. Poka-Yoke is a preventive action that focuses on identifying and eliminating the special causes of variation in production processes, which inevitably lead to product nonconformities or defects. This concept was initially called Idiot Proofing but it was understood that this name may heart workers so term Mistake Proofing was coined by Shigeo Shingo. Poka-Yoke gives a strategy and policy for preventing defects at the source. These solutions are not only cost-effective but also easy to understand and apply. It is one of the important tools to add to any organization’s Continuous improvement. In short poka-yoke is a continual improvement strategy that offers a way to move the QMS (quality management system) towards a higher level of performance.

The poka-yoke concept was generated in the mid-1960s by Shigeo Shingo who is Japanese industrial engineer. Shingo was working for Toyota and other Japanese companies, where he developed entire production systems focused on achieving zero defects in production and gave birth to this revolutionary work. The basic concept behind poka-yoke is that it is not acceptable and allowed to produce even a small amount of nonconforming product.

To stay in market and to become a world-class competitor, an organization must go with new philosophy and technology along with side by side practice of producing zero defects. Poka-yoke methods are the very easy and simple concepts for achieving this goal and are a key component of the continual improvement strategy in many leading Japanese companies on this moment. Poka-yoke is one of the presentations of “good kaizen”, or superior continual improvement because of its preventive nature. A poka-yoke device or solution is any mechanism or idea that either avoids the mistake from being made or makes the mistake easily detected at a glance. The ability to find mistakes at a glance is important because, as Shingo states, "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" He also adds to this that "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.

Need Of Mistake Proofing

When any organization decides to implement the lean manufacturing then one of the objective is to reduce scrap because no one is interested to compensate extra inventory on account of scrap. As per philosophy of lean manufacturing it focuses on speed of production and productivity also. In order to follow this concept of speed we should prevail against defects and rework. To increase profit percentage the cost pressures always become headache for top management so they never accept continued mistakes like scrap, rework, lateness etc out of tolerance instead they are aiming to achieve value of zero in this segment. When customers of any company buys product they rightfully expect defect free products and conventional 100% inspection or statistical process control don’t insure 100% defect-free products. Hence we are going to root cause of any problem and avoiding it which gives us defect free product. The above discussion concludes that to get defect free products one should go with the concept of Poka Yoke.

    1 reviews
  • Raj Janorkar

    I did not know what is POKA-YOKE means. This seminar explains it very well.

    1 year ago