Poka Yoke: ‘Fool-proof’ quality by design

The quality of offerings, be it product or service is a critical competitive differentiator for businesses. Poka Yoke is one such fool proof quality mechanism invented by Japanese with which mistakes can be avoided (rather than fixed) by design.

MyBangalore takes a simple example called ‘Poka Yoke’ and explains how it can be applied to competitive differentiation by totally avoiding defects.

When it comes to quality nobody can deny the contributions made by the Japanese. Especially in the automobile and electronic industries they re-wrote the meaning of ‘competition’ by setting new standards for quality. Today Hondas and Toyotas are the best example of ‘build-inside-sell-outside’ concept and making General Motors (GM) and Ford run for their bucks in their own country. While quality contributions by Japanese is a research subject on its own, MyBangalore takes a simple example called ‘Poka Yoke’ and explains how it can be applied to competitive differentiation by totally avoiding defects.  

Poka Yoke is a quality management concept developed by a Matsushita manufacturing engineer named Shigeo Shingo to prevent human errors from occurring in the production line. Poka yoke (pronounced ‘poh-kah yoh-kay’) comes from two Japanese words – ‘yokeru’ which means ‘to avoid’, and ‘poka’ which means ‘inadvertent errors’. Thus, poka yoke more or less translates to “avoiding inadvertent errors”. Poka yoke is sometimes referred to in English by some people as ‘fool-proofing’. However, this doesn’t sound politically correct if applied to employees, so the English equivalent used by Shingo was ‘error avoidance’. Other variants like ‘mistake proofing’ or ‘fail-safe operation’ have likewise become popular.  

The main objective of poke yoke is to achieve zero defects. In fact, it is just one of the many components of Shingo’s Zero Quality Control (ZQC) system, the goal of which is to eliminate defective products. Poka Yoke is more of a concept than a procedure. Thus, its implementation 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. Poka yoke is implemented by using simple objects like fixtures, jigs, gadgets, warning devices, paper systems, and the likes, to prevent people from making mistakes, even if they try to! These objects, known as ‘Poka-Yoke’ devices, are usually used to stop the machine and alert the operator if something is about to go wrong. Sounds different? Let us take two examples:

A major automobile manufacturing company near Bangalore has come up with an interesting metal cutting machine with ‘Poka Yoke’ in mind. In order to cut the metal parts (which are used to prepare auto-ancillary parts) the production engineers need to place the metal inside the cutting machine with both their hands and then switch ON the 'cutting' button. The main risk here would be for the engineer if he has one hand inside the machine while he switches on the machine using another hand. In order to avoid this high risk they had two 'cutting' buttons one on the left and another on the right side. Unless both buttons are pressed concurrently the cutting operation will not be started, thereby completely avoiding the error by ‘designing’ such systems. This is 'Poka-Yoke' demonstrated at its best.

Let us take some interesting examples from our own lives and see how we can apply ‘Poka-Yoke’ into it:

* Doing ‘reply-all’ for emails sometimes create unnecessary problems, unless it is intended. Disabling ‘reply all’ button by default using email clients (like Microsoft Outlook) before sending out emails to larger audience.
* Many smoke detectors are designed so they cannot be mounted on the wall until a battery is installed.
* Designing slots in consumer devices (be it printers, mobile phones, computers) in such a way that targets (cartridges, batteries, memory cards) cannot be inserted in incorrect direction.

What more Poka Yoke examples you can think of? We would love to hear from you.

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