Abstract
Human errors in work systems have occasionally a great effect on quality, safety and efficency. In order to avoid the trubles due to human errors, "fool proof" methods are adapted in various manufacturing processes. Though many factories apply the fool proof methods to their work systems, there is no general methodology to apply them.Ordinaly, the fool proof methods are derived at need in each occasion. In this article, general principles of fool proof methods are extracted from about 700 examples which are collected at assembly lines of mechanical products. As a result, 5 fundamental principles for fool proof methods-elimination, substitution, facilitation, detection of errors and relaxation of effects-are obtained. The first three are the methods fos prevention of human error occurances. The latter two are the methods for suppression of the effect of errors.
