This research presents a novel methodology for lightweighting and cost reduction of components with high structural demands by integrating advanced design and manufacturing techniques. Specifically, it combines topology optimization (TO) with additive manufacturing (AM), also known as 3D printing. Unlike conventional approaches, the proposed method first determines the optimal geometry using an artificially stiff material, and only then evaluates real materials for structural and manufacturing feasibility. This design-first, material-second strategy enables broader material screening and maximizes weight reduction without compromising performance. The proposed workflow is applied to the design of a turbofan air intake—an aeronautical component operating under supersonic conditions—addressing both structural integrity and manufacturing feasibility. Three materials from distinct classes are assessed: two metallic alloys (aluminum alloy 6061 and titanium alloy, Ti6Al4V) and a high-performance polymer (polyetheretherketone, PEEK). This last option is preliminarily discarded after being analyzed for this specific application. Finite element (FE) simulations are used to evaluate the mechanical behavior of the optimized geometries, including bird-strike conditions. Among the evaluated manufacturing techniques, Selective Laser Melting (SLM) is identified as the most suitable for the metallic materials selected, providing an effective balance between performance, manufacturability, and aerospace compliance. This study illustrates the potential of TO–AM synergy as a sustainable and efficient design approach for next-generation aerospace components. Simulation results demonstrate a weight reduction of up to 71% while preserving critical functional regions and maintaining structural integrity in Al 6061 and Ti6Al4V cases, under the diverse loading conditions typical of real flight scenarios, while PEEK remains an attractive option for uses where mechanical demands are less stringent.
Additive manufacturing (AM) has rapidly evolved from a prototyping tool into an effective method for producing end-use components, thanks to its ability to produce complex, lightweight and customised parts. However, this technique requires a thorough understanding of the long-term behaviour and degradation mechanisms of components, especially when polymers are involved in the printing process. Unlike polymer components manufactured using traditional methods, polymers produced through AM exhibit unique microstructures, anisotropies, and interfacial characteristics due to the layer-by-layer fabrication process. These features can affect how these materials respond to thermal, mechanical and environmental stresses over time. Furthermore, technology-specific processing parameters directly govern porosity distribution, crystallinity evolution, interlayer bonding quality, and residual stress development, all of which are key factors for ensuring long-term performance. This review aims to support researchers in the development of durable additively manufactured polymer components by systematically analysing polymer degradation mechanisms, accelerated ageing and lifetime prediction methodologies. Following a PRISMA-based screening process, approximately 160 international standards relevant to polymer durability in additive manufacturing were selected from an initial corpus of about 620 documents for in-depth analysis. Processing–structure–property relationships specific to the AM processing of polymers, including the commonly used FFF (fused filament fabrication), SLA (stereolithography) and SLS (selective laser sintering), are examined in relation to crucial aspects for long-term structural integrity and degradation behaviour. Finally, limitations within the current normative framework are identified, emphasising the absence of process-aware durability assessment protocols and the need for dedicated standards tailored to additively manufactured polymer components.
The optimization of Fused Filament Fabrication (FFF) process parameters is commonly performed using room-temperature mechanical properties as the main decision criteria, while the temperature-dependent thermomechanical response of printed polymers is often not explicitly considered. This limitation is relevant for functional components intended to operate above room temperature, where stiffness retention and viscoelastic behavior may strongly affect service performance. This work proposes an experimental–statistical framework for selecting FFF parameters by integrating Design of Experiments (DoE), tensile testing, dynamic mechanical analysis (DMA), Analysis of Variance (ANOVA), the Entropy Weight Method (EWM) and the VIKOR method. Two materials with contrasting thermomechanical behavior were investigated: a high-performance semicrystalline polymer, Z-PEEK, and an elastomeric thermoplastic, TPU 95A. For each material, a DoE was defined to evaluate the influence of key printing parameters, and the manufactured specimens were characterized in terms of maximum tensile force, maximum deformation and storage modulus at selected temperatures. The ANOVA results showed a material-dependent influence of the processing parameters, with thermally driven parameters being especially relevant for Z-PEEK and deposition-related parameters having a stronger influence on TPU 95A. The EWM–VIKOR analysis identified the optimal Z-PEEK configuration as 400 °C extrusion temperature, 200 °C build plate temperature and 150 °C chamber temperature, whereas the optimal TPU 95A configuration corresponded to 225 °C extrusion temperature, 0.10 mm layer height, 50 mm/s printing speed and 80 °C build plate temperature. Overall, the results demonstrate that incorporating DMA-derived thermomechanical indicators into MCDM-based optimization provides a more application-oriented basis for FFF parameter selection than approaches based only on room-temperature mechanical properties.