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Poka Yoke Concept to Prevent from Repeated Mistake

14 Oct 2016

A square peg forced into a round hole. 3D render with HDRI lighting and raytraced textures.Picture source: http://www.bing.com

By:
1. Felicia Pangestu 1801394811
2. JoshuaAdy Lubis 1801450390
3. Rich Randy 1801387333
4. Vincent Chrisnata 1801398684

Poka Yoke method was invented by a Japanese engineer, Shigeo Shingo, in 1961. Poka Yoke is derived from 2 Japanese words, “yokeru” (to avoid) and “poka” (error). When Shigo was working as an advocate on statistical process control in Toyota Motor Corporation, he realized that there were some solutions that was unable to improve manufacturing process. Therefore, he tried implementing Zero Quality Control (ZQC) with Poka Yoke as one of several methods used.  Poke Yoke is a method to avoid whimsical errors commonly caused by human error such as forgetting, fatigue, lack of focus, misunderstanding procedures, etc. Leaving the errors as they are can cause errors or defects in production process or final production results. Poka Yoke method is also an important tool for quality improvement on Six Sigma and quality assurance in Lean Manufacturing.

There are two types of approach in this method, namely:

  1. Prevent Mistake Method
    This approach is used to prevent error or trouble from happening. This method is divided into 2 kinds, namely:

Control Method
This method detects problem in a production process. If a problem is found, the production process will be halted so that the problem does not affect the other production process. As an example, a printer machine will stop as soon as it is running out of ink.

Warning Method
A like as the control method, this method also detects problem in a production process. The difference is, if a problem were found in a production process, the system will give warning signal such as light flickers or bell-ringing. For example, if an USB connector was plugged in and then someone try to detach before ejecting it, there will be a beeping sound.

  1. Detect Mistake Method

This method is used to look for error related to the process of product creation, divided into three kinds of methods, namely:

Fixed Value Method
In this method, all steps in the process is remembered, and if there were forgotten steps or movements, the system will give a warning.

Motion-Step Method
These method checks whether the whole step is already being followed correctly in the production system, so that the finished products are not defective.

Contact Method
This method finds defects in the finished products.

Application of Poka Yoke in everyday life:

  1. Parking sensor in cars that help driver to parks without colliding into other car or other objects
  2. Vehicle key, especially motorcycles, is designed in a way to ensure that when the engine is running, the key cannot be removed or detached
  3. Smartphone autocorrect, when the user accidentally misspells, the word is automatically corrected
  4. USB plugs, designed to be plugged in in a certain way

Poka Yoke’s Weaknesses:
This method is effective to prevent and find problem or error in a production system, but is not effective in fixing the problem that is already happening.Therefore, it will need other methods to fix the ongoing problem.

5S Method
5S Method, originated from Japan and is derived from the Kaizen philosophy (continuous improvement), optimizes time and cost in producing high-quality product.

  1. Seiri (Sort)
    Divide which tool or job step that is needed or not in a given job. Keep only the necessary tools / job steps and eliminate unnecessary tools / job steps.
  1. Seiton (Stabilize)
    Arrange the item placements and group the items so it will be easier to reach and operate during the production process
  1. Seiso (Shine)
    Keep the tools and workstation clean to ensure comfortable use and lighten up the user’s mood.
  1. Seiketsu (Standardize)
    Determine standards of each process in a system. Should there be any process that is done not in accordance to the standard; the production process will be disturbed.
  1. Shitsuke (Sustain)
    Maintain and preserve all the steps above, making it a standard procedure that is followed, teaching new workers about 5S and making sure they follow it.

5S’ Weaknesses:

There is actually no significant weakness of 5S. But in the beginning of its implementation, it may be difficult to be applied completely. The result of 5S implementation cannot be reached overnight; it requires persistence and diligence to fully implement this method.