Dynamic operator assignment based on shifting machine loading

This study proposes a way to improve the efficiency of semiconductor wafer fabrications by better allocating operator resources. A semiconductor wafer fabrication facility produces multiple products using unreliable machines, and each product follows a different route. Random machine failures and demand fluctuations make machine loading change from time to time. Thus, the operator assignment needs adjustment accordingly to maintain a high factory throughput rate. We propose methods to make this dynamic adjustment. By using simulation models, we demonstrate that proportionally allocating operators among all work stations based on their utilization requirements can improve overall factory efficiency. We also show that frequent short term dynamic allocation of operators produces more output than conventional long term static allocation.