Using operational planning horizons for determining setup changes

We consider operational planning horizons required for managing shop floor resources. Our concept of horizons is different from those developed in the literature for aggregate production planning; the focus is on operational-level decisions. Our problem is of scheduling machine setup changes and we conduct the study on a system implemented at a manufacturing facility. This system schedules machine setup changes at a particular stage of manufacturing. We identify a horizon parameter, l, which impacts the number of setup changes made. Short horizons increase the number of setup changes while reducing the work-in-process, whereas long horizons reduce the setups while increasing the work-in-process. We develop a metric for assessing the setup change schedules made by the system and use this to show that l is related to certain shop floor characteristics. We conclude that these characteristics should be used to determine l.