Emergy-based assessment and improvement of the selective laser melting process for multiple parts using shared support structures

• We apply emergy to analyze the environmental impact of selective laser melting. • Equipment, material, energy usage, waste, and production efficiency are analyzed. • We propose a model to normalize diverse factors for detailed emergy quantification. • Using a shared support structure to build multiple parts improves resource efficiency. • Our analysis and shared-structure method may improve additive manufacturing. Selective laser melting (SLM), a powder-bed fusion (PBF) process, is employed in aerospace and other high-end manufacturing fields because of its high precision and good formability. However, high-energy laser beams that fast-melt metal powder to form material layer-by-layer are associated with problems such as excessive energy usage, lengthy production cycles, and inadequate equipment efficiency. Additionally, using an extremely fine powder also leads to high costs and major environmental impact during production. Therefore, the ecological influence and sustainability of SLM are important. Unlike conventional LCA, emergy analysis provides a unified metric for diverse environmental inputs, enabling a more holistic sustainability assessment of SLM systems. We use the emergy theory to analyze and evaluate the environmental impact of SLM by establishing an emergy flow model comprising resource consumption, waste, labor, time, quality, and costs. In the model, environmental impact factors are classified into unified emergy equivalents, and evaluation criteria for a system sustainability index are established. Analysis results indicate that SLM systems exhibit high environmental influence and low production efficiency. To improve the system sustainability, we introduce a shared support structure design method for simultaneously forming multiple parts. Simultaneously processing multiple parts in the SLM system reduces the energy usage, material utilization, and environmental impact per part. Case study results demonstrate that the shared support structure method reduces energy consumption by 5.5 %, support material usage by 17.2 %, and improves the sustainability index ( SI ) by 1.04 %. The method has the potential to improve sustainability of PBF, while increasing production efficiency and feasibility.