This paper focuses on the appropriate selection of suppliers and assigning order quantities to them. This problem contains multiple objectives and their related constraints and utilizes fuzzy decision making in its solution approach. In the proposed model, goals, constraints, variables and coefficients are all fuzzy. It is shown that with the application of the fuzzy methodology, the multiy objective problem is converted to a single one that can be solved easily.

Positive performance of purchase department directly affects the lowering costs, increasing profitability and stability of a supply chain. Evaluating and selection of suppliers is considered on of the main responsibilities of purchase department in a supply chain. In this paper, in order to solve the problem of supplier selection, a fuzzy none linear multi objective model is presented. This model enables the decider to allocate different weights to different objective regarding its specific strategies. In addition, the possibility of using the model in conditions which loading costs are imposed to the buyers should be considered after calculating total purchase costs (materials procurement, load and maintenance). In the proposed model, the ambiguity in ranking different objective is considered by using the FAHP. In this article, for the first time the membership function of fuzzy numbers observed as trapezoidal.

Suppliers are one of the most vital parts of supply chain whose operation has significant indirect effect on customer satisfaction. Since customer's expectations from organization are different, organizations should consider different standards, respectively. There are many researches in this field using different standards and methods in recent years. The purpose of this study is to propose an approach for choosing a supplier in a food manufacturing company considering cost, quality, service, type of relationship and structure standards of the supplier organization. To evaluate supplier according to the above standards, the fuzzy inference system has been used. Input data of this system includes supplier's score in any standard that is achieved by AHP approach and the output is final score of each supplier. Finally, a supplier has been selected that although is not the best in price and quality, has achieved good score in all of the standards.