Rolling Schedule Policies in Multiple-Item Systems

In uncertain environments, the master production schedules of end items are usually determined using rolling schedules. This paper discusses rolling schedule policies for production systems with multiple end items and uncertain demands. The rolling schedule policies mean the methods for choosing frozen and replanning intervals of rolling schedules. They include the individual policy, the common policy, and the intermediate policy. The experimental results indicate that, in a system with multiple end items, the choice of rolling schedule policy depends on the deviation of individual item's natural cycles among items. When the deviation is low, all items can be grouped as a product family and a common policy can be applied. When the deviation is high but these end items are less expensive, all items may be grouped as a product family and a common policy can be applied. When the deviation is high and these end items are expensive, managers should consider to use the intermediate policy, that is, group these items into several product families, and apply a common frozen and replanning intervals to each product family.