Evaluation of the Human Error Probability in Cellular Manufacturing

Referring to Gutenberg there are three elementary production factors: material, equipment and human workforce. They all have a significant influence on the product quality. Nevertheless, in machining research they have been given differing attention, depending on the focused scope. This paper presents the results of an empirical study of the human error probability (HEP) in a Cellular Manufacturing environment. First, it is shown that the influence of human work on the resulting product quality in machining so far has only been given little attention. Therefore a content analysis according to Mayring has been conducted on publications in the domains of production technology and ergonomics. Second, various schemes for the classification of human errors are presented and evaluated in terms of their applicability to human tasks in machining. Finally the design and results of an empirical study which has been conducted at the Cellular Manufacturing reference line, consisting of two lathes and four milling machines, in the Center for industrial Productivity (CiP) at TU Darmstadt are presented. Overall 2700 human-machine interactions have been observed and evaluated in terms of their influence on product quality. Results show that there is a significant influence of the human worker as three percent of these interactions incorporated a spurious action