Overtime decision rule experiments with a model of a real shop

Simulation experiments are described in which the impact was examined of changes in the decision rules used to control overtime, on the cost performance of a model of an actual make-for-stock shop. The effect was investigated of changes in both the rate at which the level of overtime was adjusted, and in the basis on which the amount of overtime was set. As anticipated, increasing the rate of adjustment did lead to significant cost savings across the full range of conditions examined. However, the magnitudes of these savings were found to be unexpectedly small. The effect was examined of changing the basis on which the amount of overtime was set to one designed to cause overtime to be worked at earlier operations in the manufacturing process. This change did not produce consistent improvements in performance across the range of the stock-out cost rates considered.