A Bi-objective Closed Loop Supply Chain with Different Machinery Options: Application of Fuzzy Weighted Additive Approach

Supply chain management is an emerging area that drawing increasing attention of academics and practitioners for decades. In recent years, SCM's focal point has begun to emerge as a sustainable flow management, in which economic, social and environmental aspects such as energy consumption, carbon emissions are jointly addressed. This study focused on formulating and solving a bi-objective multi-period closed loop supply chain network design problem. The model determines the production and distribution strategies, while minimizing two objectives simultaneously; the total supply chain cost and the carbon emissions generated by plants operating through different machinery types. While the initial purchase cost of older and more outdated machinery is lower than newer ones, older machinery emits greater amount of carbon per hour as opposed to newer machinery while operating at even greater cost per hour. Besides, the number of products produced in an hour is also higher in newer machinery. We adopted a fuzzy weighted additive approach to solve the bi-objective optimization model. The results confirm that investing in newer technologies in manufacturing comes with great result for both economic and environmental causes, reducing the unit cost and carbon emission per product throughout the manufacturing periods