The relationship between the physical layout of the work stations and the productivity of a saturated single-hoist production line

Over the past fifteen years a growing number of research workers have become interested in the problem of how to optimize the productivity of treatment lines fed by one of several hoists. Their work has concentrated mainly on scheduling the moves of the hoist. However, the layout of the stations is always taken as a constant. The aim of this paper is to underline the relationship between the physical layout of the stations and the productivity of a treatment line. We focus on saturated single-hoist production lines. After introducing a model of this problem, we focus on a particular class of layout that is commonly used by industrial users. We show first that this class does minimize the hoist moving time during a cycle time. In the following part, we show that this particular class of layout is, however, not dominant in all cases for maximizing the productivity of the line. Before concluding our study, we propose a branch and bound algorithm to process the optimal layout for maximizing the productivity of a saturated single-hoist production line. The studies show that this procedure is very efficient.