A three layer multi-item production–inventory model for multiple suppliers and retailers

The paper deals with a production inventory model for various types of items where multiple suppliers, a manufacturer and the multiple non-competing retailers are the members of the supply chain. In this model, each supplier supplies only one type of raw material to the manufacturer. The manufacturer produces a finished item by the combination of certain percentage of the various types of raw materials. The manufacturer produces also multi-items and delivers them according to the demand of the different retailers. Finally, an integrated profit of the supply chain is optimized by optimal ordering lot sizes of the raw materials. A numerical example is provided to justify the proposed model.