 Levinson Productivity
Systems, P.C.William A. Levinson, P.E. Principal 570-824-1986  |
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The idea is to prevent mistakes as opposed to relying on operator vigilence. (A work instruction that calls for "operator vigilence" is a sign that the job can be improved by error-proofing.)
 Animation
of a poka-yoke device. Metal plates sometimes entered tooling upside-down.
This was prevented by installation of the fixture shown at left; parts
cannot get through the chuck unless they are properly aligned.
Shingo, Shigeo. 1986. Zero Quality Control: Source Inspection and the Poka-Yoke System. Portland, OR: Productivity Press. Page 175. |  Error-proofing
through product design. The two parts cannot be assembled in any but the
desired orientation. |