Recent improvements in additive layer manufacturing (ALM) have provided new designs of geometrically complex structures with lighter materials and low processing costs. The use of additive manufacturing in spacecraft production is opening up many new possibilities in both design and fabrication, allowing for the reduction of the weight of the structure subsystems. In this aim, polymeric ALM structures can become a choice, in terms of lightweight and demisability, as far as good thermomechanical properties. Moreover, provided that fused-deposition modeling (FDM) is used, nanosats and other structures could be easily produced in space. However, the choice of the material is a crucial step of the process, as the final performance of the printed parts is strongly dependent on three pillars: design, material, and printing process. As a high-performance technopolymer, polyether ether ketone (PEEK) has been adopted to fabricate parts via ALM; however, the space compatibility of 3D-printed parts remains not demonstrated. This work aimed to realize a nanosat polymeric structure via FDM, including all the phases of the development process: thermomechanical design, raw material selection, printing process tuning, and manufacturing of a proof of concept of a technological model. The design phase includes the application of topology optimization to maximize mass saving and take full advantage of the ALM capability. 3D-printed parts were characterized via thermomechanical tests, outgassing tests of 3D-printed parts are reported confirming the outstanding performance of polyether ether ketone and its potential as a material for structural space application.
Permanent Rare Earth magnets are becoming more and more important in efficient motors and generators with high energy density. Among them NdFeB magnets are the most employed, with NdFeB having higher remanence, high coercivity and energy product. Nevertheless,their poor corrosion resistance makes them susceptible to degradation of the magnetic properties. One possible solution is the development of innovative polymeric composite magnetic materials. The preparation of NdFeB powders filled polymeric matrix (PEEK), with a double goal of protecting the magnetic alloy is proposed, thus preventing it from corrosion, and to realize a new material that can be shaped in the form of filaments. This material was used as feedstock in the 3D printing process to produce high performance magnets with customized and optimized design. The PEEK-NdFeB filaments were produced with three percentages of filler amount(i.e. 25, 50 and 75 wt%). PEEK neat filaments were produced as reference. The influence of the filler on the main thermomechanical properties of the resulting composites, as well as its effect onthe 3D printing process were evaluated by means of different investigation techniques (DSC, DMTA, XRD, tensile testing). The magnetic properties exhibited by Fused Filament Fabrication (FFF) printed parts confirmed the feasibility of employing such a combination of an innovative manufacturing technique and high-performance PEEK-NdFeB compounds.The characterization carried out on both neat and composite filaments evidenced that the presence of the filler slightly decreased the thermal stability, increased the elastic modulus while decreasing ductility and maximum tensile strength. By means of DSC analysis, it was confirmed that the crystallinity is influenced by the presence of the filler. Magnetic measurement performed on the 3D printed parts demonstrate that interesting magnetic properties were achieved, confirming the feasibility of the magnetic 3D printed composite with PEEK.