Combining topology optimization with targeted application of LMD additive manufacturing - A prospective LCA of laser-based aluminum processing

Mechanical engineering, as a leading industry, offers the potential to increase resource and energy efficiency for the targeted implementation of sustainable value chains. The application of laser-based processes, especially laser-based additive manufacturing, enables the production of thin-walled, complex, and functionally integrated structures with a high stiffness-to-weight ratio, making them ideal for lightweight applications. However, a disadvantage of laser-based processes is the significantly higher energy demand compared to conventional methods. This suggests that manufacturing lightweight components while keeping the amount of additive manufacturing at a minimum should be environmentally favorable. The subject of the investigation is to test this hypothesis on an aluminum-based component from the automotive sector and its topology optimized counterpart. For that purpose, a hybrid manufacturing route—including laser cutting, laser welding, and laser-based additive manufacturing—is compared to two reference routes depicting conventional manufacturing and purely additive manufacturing by means of a life cycle assessment (LCA). The assessment is partly based on primary data from experiments, covers production and use phase and also considers future energy conditions through the incorporation of integrated assessment models in form of prospective LCA. The results show that minimizing the share of additive manufacturing within a topology-optimized component can reduce environmental impacts drastically. But compared to conventional manufacturing impact savings are still only achieved under future energy conditions.