Shahid Beheshti University Journal of Industrial Management Perspective 2251-9874 15 3 2025 09 23 Presenting a multi-product and multi-period mathematical model for sustainable supplier selection and development (Case study: Zamiad automotive company) Presenting a multi-product and multi-period mathematical model for sustainable supplier selection and development (Case study: Zamiad automotive company) 32 57 106027 10.48308/jimp.15.3.32 FA Neda Asili MSc, Department of Industrial Engineering, Faculty of Industrial Engineering, University of Science and Technology, Tehran, Iran. Ebrahim Teimoury Professor, Department of Industrial Engineering, Faculty of Industrial Engineering, University of Science and Technology, Tehran, Iran. 0000-0003-3083-1609 Journal Article 2025 02 06 Introduction and Objectives: Supply chain management in today’s economic and competitive environment has been challenging for many decision-makers. The presence of multiple suppliers with different quality levels, high production and transportation costs, and expectations regarding product quality has caused suppliers to compete based on acceptable criteria. Moreover, the modern perspective on supply chains has shifted from the traditional view, and sustainability criteria, including environmental, social, and economic factors, have received increased attention among researchers. Supplier development is a form of collaboration between manufacturers and suppliers. This study aims to propose a two-stage mathematical model for supplier selection and development and to evaluate its performance in Zamyad Company (automotive industry). Methods: In the first stage, the competency of existing suppliers is evaluated, and those lacking the minimum required score to compete are prevented from entering the second stage. In the second stage, selected suppliers are identified, and their production quantities for each production period are planned. The model also considers production planning for suppliers, and suppliers are allowed to have backorders in their inventory. In addition to production planning, the characteristics of multi-period and multi-product environments are also taken into account. Due to the non-uniform nature of the objective functions, the mathematical model was linearized using the weighted sum method, converting it into a single-objective linear model. The model was solved using GAMS software. Results and Discussion: The results indicate that considering a multi-period environment adds two key capabilities to the model: first, it allows suppliers to meet demand with backorders, which reduces overall supply chain costs; second, it enables existing suppliers to develop their performance across all or some criteria in each production period. Moreover, the multi-product environment allows all suppliers to compete to supply at least one product, providing greater flexibility in supplier selection. Suppliers who can improve their performance in the accepted criteria for a specific product can be considered as candidates for supplying that product. Conclusions: The proposed mathematical model, considering multi-product and multi-period environments, provides an effective tool for supplier selection and development, facilitating optimal decision-making for companies. The results suggest that this model can reduce supply chain costs, improve the performance of existing suppliers, and allow new suppliers to enter the competitive environment. Introduction and Objectives: Supply chain management in today’s economic and competitive environment has been challenging for many decision-makers. The presence of multiple suppliers with different quality levels, high production and transportation costs, and expectations regarding product quality has caused suppliers to compete based on acceptable criteria. Moreover, the modern perspective on supply chains has shifted from the traditional view, and sustainability criteria, including environmental, social, and economic factors, have received increased attention among researchers. Supplier development is a form of collaboration between manufacturers and suppliers. This study aims to propose a two-stage mathematical model for supplier selection and development and to evaluate its performance in Zamyad Company (automotive industry). Methods: In the first stage, the competency of existing suppliers is evaluated, and those lacking the minimum required score to compete are prevented from entering the second stage. In the second stage, selected suppliers are identified, and their production quantities for each production period are planned. The model also considers production planning for suppliers, and suppliers are allowed to have backorders in their inventory. In addition to production planning, the characteristics of multi-period and multi-product environments are also taken into account. Due to the non-uniform nature of the objective functions, the mathematical model was linearized using the weighted sum method, converting it into a single-objective linear model. The model was solved using GAMS software. Results and Discussion: The results indicate that considering a multi-period environment adds two key capabilities to the model: first, it allows suppliers to meet demand with backorders, which reduces overall supply chain costs; second, it enables existing suppliers to develop their performance across all or some criteria in each production period. Moreover, the multi-product environment allows all suppliers to compete to supply at least one product, providing greater flexibility in supplier selection. Suppliers who can improve their performance in the accepted criteria for a specific product can be considered as candidates for supplying that product. Conclusions: The proposed mathematical model, considering multi-product and multi-period environments, provides an effective tool for supplier selection and development, facilitating optimal decision-making for companies. The results suggest that this model can reduce supply chain costs, improve the performance of existing suppliers, and allow new suppliers to enter the competitive environment.

https://jimp.sbu.ac.ir/article_106027_3c10b3ad8f1ed39cca3212b7dca0b6ec.pdf