Coping with finite storage space in job shops through order release control: an assessment by simulation

Most literature on job shops assumes that an infinite storage space is available on the shop floor. But in practice, storage space is limited or finite. The job shop control problem with finite storage space has received little attention; it is a complex problem for which optimised scheduling may lead to unfeasible and poor quality solutions. The alternative to a scheduling solution is the use of controlled order release. This study uses simulation to assess the performance of four order release control rules. Results indicate that the best results are achieved by the workload control order release (WLCOR) rule. This rule produces results comparable to the optimum solution identified by analytical modelling in terms of the storage space required to achieve a certain production rate. The advantage of WLCOR is that it does this while simultaneously controlling lead times and the percentage of tardy jobs. Results have significant implications for practice, particularly where space is at a premium.