Supplier numbers optimization based on risk theory

It is important to choose the number of suppliers in supply chain risk management. Too small number of suppliers will make the supply risk increasing, and excessive number of suppliers will increase the company´s purchasing costs. This paper first transforms the supply risk of suppliers into supply system reliability. Then it quantitatively analyses the relationship between the number of suppliers and purchasing cost and reliability. It establishes a multi-objective optimization model for the number of suppliers. Finally, combining with a numerical example, the paper verifies the validity of the model.