An inventory system of raw materials for a single product is considered. The raw materials are assumed to be consumed only during each production period. The system aims to determine the optimal manufacturing cycle for the product and the optimal procurement quantities for the raw materials.
It is proved that there exists a unique optimal policy that minimizes the associated annual inventory system cost. It is further shown that the inventory system is directly applicable to some single-machine multi-product scheduling problems.
A computational procedure for determining the optimal procurement quantities is presented. Even if the joint replenishment of raw material is feasible, an economic policy can be obtained by a search procedure.