Sustainability assessment of autoclave and 3D printed composites with thermosetting and thermoplastic matrices

This study compares the environmental and economic impacts of three manufacturing methods for continuous fiber-reinforced composites: traditional autoclave molding (Scenario 1) and two 3D printing technologies, one using thermosetting resin (Scenario 2) and the other using thermoplastic resin (Scenario 3). Life cycle assessment (LCA) and life cycle cost (LCC) analyses were performed for components with the same geometry, stiffness, and load capacity. Results show that Scenario 1 has the highest environmental impacts, of about 1.87 kg CO2 eq, primarily due to material waste and energy-intensive curing processes. In contrast, 3D printing minimizes material waste, reducing overall impacts to 1.39 kg CO2 eq, with the thermoplastic-based composites in Scenario 3 offering additional benefits through recyclability. However, due to their lower mechanical properties, thicker and heavier parts are required in Scenario 3, leading to higher impacts in structural applications. Scenario 2 presents a balanced solution with similar mechanical properties to traditional composites and lower environmental impacts (1.30 kg CO2 eq). From what concerns the total costs, Scenario 1 resulted as the most costly solution (€ 105.27), while Scenario 3 represents the cheapest alternative (about € 37.89) if high mechanical performances are not necessary. If high mechanical properties are required, the most sustainable alternative both economically and environmentally is represented by Scenario 2. The findings suggest that 3D printing is a promising, cost-effective alternative to traditional methods, particularly for non-structural applications, and point to future improvements in composite manufacturing through material optimization and recycling.