Decision support model of environmentally friendly and economical material strategy for life cycle cost and recyclable weight

Materials and parts selection in product design phase will affect procurement cost, assembly cost and recycling costs in manufacturing phase. Similar to such costs, recyclable weight depends on material types due to different material manufacturing processes. As material shortages have increased, environmentally friendly and economical material selection is required. Since assembly products consist of various parts made of different materials, it is difficult and complex to evaluate recyclable weight and costs simultaneously in the assembly product design. This selection is considered as a multi-criteria decision-making problem in which objective functions have trade-off relationships. Thus, a decision support model is required to enable product designers to evaluate alternative material in terms of both environmental and economic aspects among procurement, assembly, and recycling. As a method of solving the multi-criteria decision-making problems, goal programming is recognized as one of the effective ways of evaluating the different objective functions simultaneously. This study proposes a decision support model of environmentally friendly and economical material strategy for life cycle cost and recyclable weight. The developed model contributes to proposing candidate materials for the assembly products in the concept design phase since the model requires only inputting the material type and weight for each part to evaluate cost and recyclable weight. First, the procedures regarding alternative material selection are explained. Next, the procurement, assembly, and recycling costs are estimated based on the material types and assembly/disassembly tasks and weights. In addition, the environmental loads, such as the recyclable weight for each part, are calculated based on the material types and weight. Third, the alternative material selection is formulated as a bi-objective problem by goal programming for minimizing costs such as procurement, assembly, and recycling costs for minimizing recyclable weight. Finally, a case study is presented and analyzed in terms of the environmental and economic aspects among procurement, assembly, and recycling.