6. Conclusion
In this paper, a novel comprehensive approach is developed to solve the sustainable supplier selection and order allocation problem, simultaneously. Therefore, a multi-product, multi-item, multi-supplier and multi-period model with quantity discount consideration was designed.
Identification of economic, environmental and social criteria and their definition according to expert’s opinion and literature was the first step to implement the proposed approach. Then, the fuzzy MOORA method is applied to obtain suppliers score and rank. However, to have a better and more accurate judgment about supplier’s sustainability indices, it is necessary to consider suppliers risks within the fuzzy MOORA. Hence, FMEA technique has been used in this study to obtain risk values for each supplier. In the next step, the results of integrating the FMEA and fuzzy MOORA are imported as parameters for the third objective function. The efficiency and applicability of the proposed approach are illuminated with a case study of the evaporative cooler in a home appliance industry by considering four products, six items, eight suppliers and four periods in one-year planning horizon.