Comparative LCA of conventional manufacturing vs. additive manufacturing: the case of injection moulding for recycled polymers

Additive Manufacturing helps to develop production alternatives with new technologies and less environmental impacts. The comparative analysis was performed between two manufacturing processes using black recycled Acrylonitrile Butadiene Styrene (ABS) pellets to evaluate the potential environmental impacts between Injection moulding and Fused Deposition Modelling (FDM). The Life Cycle Assessment (LCA) and the Unit Process Life Cycle Inventory (UPLCI) methodology were adopted, which resulted in an impact assessment separated by operation modes and subunits of the equipment. The LCA results indicate a lower environmental impact of the FDM when the aim is to produce a batch size smaller than 14 parts. For batch sizes above 50 parts, the Injection moulding process generated less impact to the Global Warming Potential (GWP) and Cumulative Energy Demand (CED). The printing stage contributed the most to generating impacts for the FDM. In the Injection moulding process, the main responsible for generating impacts were the injection phase. Mechanical tensile tests were carried out with the parts obtained by the FDM with different infills (25%, 50%, 75% and 100%), and it was observed that parts with 100% infill obtained the best relation between mechanical properties and environmental impacts.