Virgin or recycled? Optimal pricing of 3D printing platform and material suppliers in a closed-loop competitive circular supply chain

Three-dimensional printing (3DP) or additive manufacturing is regarded as an environmentally friendly and sustainable form of manufacturing, which allows circular manufacturing as the 3D printed waste and products can be recycled for further 3DP operations. Due to the fact that the reclaimed material is commonly perceived to have poorer quality than the virgin material, the pricing of materials and printed products are crucial for consumers to decide their printing and material selection decisions. We consider a closed-loop competitive circular supply chain comprising (1) a 3DP platform that provides 3DP services to print products from virgin and recycled materials, (2) material suppliers that provide virgin and recycled materials (filaments) for the platform, and (3) end users who use the platform to print their products. We derive the prices, demands, and profits of the 3DP platform and material suppliers in Stackelberg equilibrium. We also conduct numerical studies using real-life data to generate practical insights from the analytical findings. Most interestingly, we find that while the platform prefers, both types of suppliers avoid, printing high-quality products from recycled material. We derive management insights and policy implications from the analytical and numerical findings for the closed-loop competitive circular supply chain.