Alternative order release mechanisms: A comparison by simulation

Releasing mechanisms are the set of rules which determine when matured orders i.e. those confirmed orders for which materials and tools are available, are dispatched to the shop floor so that processing can commence. This paper presents a simulation in which three such mechanisms are compared with a scenario in which matured orders are automatically released. Two of the mechanisms assume that the set of jobs to be released is given and that capacity cannot be adjusted. In contrast, the third rule allows capacity to be adjusted both as new jobs enter the system and as they are released to the shop floor. The simulation study shows that the latter rule is the best releasing rule under delivery performance and workload measures, but is slightly worse under the workload balance measure. This high performance is achieved at a relatively low cost in terms of increased capacity. In comparison with a scenario in which mature orders are automatically released to the shop, the latter rule performs better under all criteria except the proportion of tardy orders. It is concluded that further research is needed to show whether order release mechanisms can improve all delivery criteria as well as workload criteria.