Optimización de estrategias para el diseño orientado a la fabricación aditiva (DfAM) de piezas metálicas aligeradas por deposición de energía focalizada (DED)
Authors:   , Uralde Jiménez Virginia 
Published: November 2024

This Thesis examines various stages of the metal additive manufacturing flow, with a special focus on Directed Energy Deposition-Arc (DED-Arc) technology and its knowledge to guide design for optimal manufacturing. Each study addresses a specific objective, motivated by the current limitations of this technique. In the preliminary phase, a tool for the optimal selection of additive manufacturing technology is developed using the Analytical Hierarchical Process (AHP) methodology, known for its effectiveness in multi-criteria decision making. The results indicate that the reliability of the technique is the most important criterion when selecting a manufacturing technology. This tool makes it possible to identify the most suitable technology for specific applications, optimising resources and improving the quality of the final product. The experimental phase focuses on the study of different deposition strategies. First, symmetry in fabrication is investigated using overlap and oscillation techniques, evaluating how the geometrical configuration and the deposition technique affect the quality and mechanical properties of the deposited material. The main results show that the oscillation strategy produces better results in terms of symmetry compared to the overlap strategy. Subsequently, four different trajectories for tackling a cross intersection are compared in order to identify the optimal trajectory. The intersection based on Cross-Overlapping, Cross-Waving, a variable amplitude oscillating trajectory (Waving) and the Overlapping of curved trajectory (Overlapping) are compared. This analysis is crucial, as the intersections in the paths can be critical points where stresses concentrate and defects originate. Their proper selection not only improves the structural integrity of the manufactured parts, but also optimises production time and costs. The study has shown that the Cross-Overlapping and Cross-Waving strategies produce the optimal geometries, while the Waving strategy required fewer stops per layer. Finally, the fabrication of a wall by combining two materials through overlapping and overlapping (material hybridisation) is explored. The results have shown that it is possible to manufacture walls with two metals without any defects in the intermetallic area. No visual defects, pores or cracks in the microstructure were observed. The bimetallic walls retain the microstructure corresponding to each separate material. This study allows to explore new hybrid properties and to improve the performance of the final parts. Finally, the design of a real case is presented: an aeronautical tooling part oriented to additive metal manufacturing (DfAM). This case study synthesises the knowledge acquired in the previous phases. The implementation of DfAM in the design of this part has allowed a 63% reduction in the weight of the initial part, optimising its performance and efficiency. This demonstrates how a thorough understanding of additive manufacturing techniques can transform the design process, reducing costs and mitigating the ecological impact of production. This Thesis contributes to theoretical knowledge and has significant practical applications of the technology, demonstrating that informed design can improve all aspects of additive manufacturing.