SETTING THRESHOLDS FOR PERIODIC ORDER RELEASE

In job shop manufacturing environments, controlling the release of wor k orders can significantly improve system performance, especially when a few bottleneck resources limit shop throughput. A periodic order re lease policy measures the remaining workload of the bottlenecks and re leases just enough work orders to bring the workload to specified thre shold values. The thresholds should limit the work-in-process inventor y but not delay order completion by starving the bottlenecks. In this paper we consider the problem of setting thresholds that minimize the expected cost of work-in-process inventory and order tardiness. For th e single-bottleneck system, we propose a stochastic optimization appro ach that uses smoothed perturbation analysis to estimate the objective function gradient. Our computational experiments compare different me thods that set good threshold values and show that periodic order rele ase improves system performance.