Tuesday, March 25, 2008


What causes defects ?

1.Inappropriate procedures or standards
2.Excessive variability happens during actual operations
3.Damaged or excessively variable materials
4.Worm machine parts (for example, bearings or tools)
5.Human mistakes

The fact is, human geings are very forgetful and tend to make mistakes. Too often we blame people for making mistakes. Especially in the workplace, this attitude not only discourages workers and lowers morale, but it does not solve the problem. POKA YOKE is a technique for avoiding simple human error at work.

Poka Yoke or Error Proofing has existed for a long time in various forms, it was Japanese manufacturing engineer " Shigeo Shingo " who developed the idea into a formidable tool for achieving Zero Defects and eventually eliminating quality control inspection. Generally translated as "Mistake-Proofing " to avoid = Yokeru , Error = Poka ". The idea behind Poka Yoke is to respect the intelligence of workers. By takng over repetitive tasks or actions that depend on vigilance or memory, Poka Yoke can free a worker's time and mind to pursue more creative and value adding activities.

There are 10 different of errors :

  1. Forgetfulness ; Sometimes we forget things when we are not concentrating. Safeguards : Alerting operator in advance or checking at regular intervals.
  2. Errors due to misunderstanding ; Sometimes we make mistakes when we jump to the wrong conclusion before we're familiar with the situation. Safeguards : Training, checking in advance, standardizing work procedures.
  3. Error in identification ; Sometimes we misjudge a situation because we view it too quickly or too far away to see it clearly. Safeguards : Training, attentiveness, vigilance
  4. Errors made by amateurs ; Sometime we make mistakes through lack of experience. Safeguards : Skill building, work standarization.
  5. Willful errors ; Sometimes errors occur when we decide that we can ignore rules under certain circumstances. Safeguards : Basic education and experience.
  6. Inadvertent errors ; Sometimes we are absentminded and make mistakes without knowing how they happened. Safeguards : Attentiveness, discipline, work standardization.
  7. Errors due to slowness ; Sometimes we make mistakes when our actions are slowed down by delays in judgment. Safeguards : Skill building, work standarization.
  8. Errors due to lack of standards ; Some errors occur when there are no suitable instructions or work standards. Safeguards : Work standaridization, work instructions.
  9. Surprises errors ; Errors sometimes occur when equipment runs differently than expected. Safeguards : Total productive maintenance (TPM) , work standarization.
  10. Intentional errors ; Some people make mistakes deliberately, crimes and sabotage are example. Safeguards : Fundamental education, mindset training with positive thinking, discipline.

3 Strategies for Zero Defects

  1. Don't make it !!! Don't make products that you don't need. More products you make, then greater the opportunity for defects as they sit in inventory. That why follow " Just In Time " principle and make only what is needed, when it is needed and in the right amount needed.
  2. Make it to withstand any use !!! The user in an expert at finding defects. Therefore it is important to build safeguards into the production process to ensure that product can withstand any use. Quality can be built inti products by thoroughly implementing Poka Yoke, automation, and work standarization.
  3. Once you have made it, use it right away !!! If a product cannot be made to withstand any use, then make sure it is used as soon as possible by using continuous flow production.
Have a nice try and find "POKA YOKE" in your production system.