Poka-Yoke

In the 2016 ASQ World Conference Recap email issued June 1, 2016, the Quality tool of the week is Mistake Proofing, or Poka-Yoke.  The full article is available on the ASQ National website click here.

Mistake–Proofing Procedure

  1. Obtain or create a flowchart of the process. Review each step, thinking about where and when human errors are likely to occur.
  2. For each potential error, work back through the process to find its source.
  3. For each error, think of potential ways to make it impossible for the error to occur. Consider:
    • Elimination—eliminating the step that causes the error.
    • Replacement—replacing the step with an error-proof one.
    • Facilitation—making the correct action far easier than the error.
  4. If you cannot make it impossible for the error to occur, think of ways to detect the error and minimize its effects. Consider inspection method, setting function and regulatory function.
  5. Choose the best mistake-proofing method or device for each error. Test it, then implement it. Three kinds of inspection methods provide rapid feedback:
    • Successive inspection is done at the next step of the process by the next worker.
    • Self-inspection means workers check their own work immediately after doing it.
    • Source inspection checks, before the process step takes place, that conditions are correct. Often it’s automatic and keeps the process from proceeding until conditions are right.

If you do Poka-Yoke and would be willing to share your experiences at either a section workshop or dinner meeting please contact the Section Leadership Committee.