POKA-YOKE
Poka-yoke is a method for building quality into a manufacturing process (versus trying to catch product defects after they are made through inspections and the like.) True poka-yoke does not involve an extra step or an extra process--- it is integrated into the process that actually makes the product.
The term poka-yoke originated in Japan during the early 1960s. It is a euphemism for another term: baka-yoke, which means “avoiding stupidity.” Poka-yoke is best translated as “mistake-proofing.”
A poka-yoke device often makes it impossible for a worker to continue a process if a mistake is made. If this is not practical, the poka-yoke may issue a warning.
For example, a sensor may verify that all the components of an assembly have been included before a workpiece can be released to the next process. If a component is missing, the sensor triggers a mechanism that sounds an alarm and/or stops the line.