When it comes to manufacturing, the best assembly process in the world can still fall prey to such prosaic constraints as operator fatigue, inattentiveness, time pressure, and plain-old carelessness. The results-scrap, waste and decreased profits-are something manufacturers can ill afford in a competitive world.
To maximize quality and efficiency, U.S. manufacturers are increasingly embracing the Japanese concept of poka-yoke (pronounced POH-kah YOH-kay), or mistake-proofing. Poka-yoke devices are mechanisms that prevent mistakes from being made or that make mistakes obvious at a glance. Besides reducing the cost of scrap, rework and warranty claims, mistake-proofing provides a less obvious benefit: It gives workers time to think about how to improve the assembly process. Instead of acting as mere extensions of their machines, operators are free to manage their environment.