Dealing with a shelf life constraint in cyclic scheduling by adjusting both cycle time and production rate

The situation of a family of items sharing a piece of production equipment is considered. Known level demand rates are assumed. The items are scheduled in a cyclic fashion where the production cycles through all of them every T units of time. There are shelf life limits for each of the items. The paper deals specifically with the situation where the cost-minimizing T leads to the violation of one of the shelf life constraints. Removing the infeasibility by simultaneously adjusting T and the production rate of the item concerned is shown to be at least as good as adjusting just one of these parameters.