Stereolithography (SL) additive manufacturing process provides increased dimensional precision, smooth surface finish and printing resolution range in the order of magnitude of 100 μm, allowing to obtain intricate 3D geometries. The incorporation of ceramic-based inclusions within liquid resins enhances the thermal and mechanical properties of the final 3D printed component while improving the surface finishing of the final parts; in this way, it expands the range of process applications and reduces the post-processing steps. The proposed approach investigates the bulk modification of commercial SLA resins mixed with ceramic powders of Al₂O₃ (grain size 1–10 μm) and SiO₂ (grain size 55–75 nm) aiming to improve 3D printed parts performance in terms of mechanical properties, dimensional stability and surface finishing compared with pure, unmodified resins. The produced materials were used for the development of inserts for injection moulding and were examined for their performance during the injection moulding process. The addition of particles in the nano- and micro-range is being employed to improve parts performance for rapid tooling applications whilst maintaining 3D printing accuracy, thermal and mechanical properties as well as achieving a smooth surface finishing compared with unmodified resins.

This study aims to develop a comprehensive process to evaluate the leaching behavior of 3D-printed nanocomposite samples as candidate materials for potential use in wearable devices. The study involves the immersion of the 3D-printed test coupons, produced via Fused Filament Fabrication (FFF), into artificial sweat and deionized water in a controlled environment provided by a dissolution apparatus. Three distinct nanocomposite filaments were used, each consisting of different polymer matrices: thermoplastic polyurethane (TPU), copolyester (TX1501), and polyamide (PA12). The additives incorporated within these filaments encompassed silver nanoparticles (AgNPs), chopped carbon fibers (CCFs), and super paramagnetic iron oxide nanoparticles (SPIONs), respectively. The current study aims to identify potential risks associated with the release of nanomaterials and additives, through SEM/EDX analysis and in vitro measurements of proinflammatory cytokines. Furthermore, this research contributes to the advancement of safe and reliable 3D-printed materials for wearable technologies, fostering their widespread adoption in various applications.

Fused filament fabrication (FFF) is a popular additive manufacturing (AM) method for creating thermoplastic parts with intricate geometrical designs. Pure thermoplastic materials utilized in FFF, whose polymeric matrix is reinforced with other materials, such as carbon fibers (CFs), introduce products with advanced mechanical properties. However, since not all of these materials are biodegradable, the need for recycling and reuse immediately emerges to address the significant problem of how to dispose of their waste. The proposed study evaluates the printability, surface morphology and in vitro toxicity of two thermoplastic-based composite materials commonly used in wearable device manufacturing to provide enhanced properties and functionalities, making them suitable for various applications in the field of wearable devices. Tritan Copolyester TX1501 with 7.3% chopped CFs (cCFs) and Polyamide 12 (PA12) with 8.6%cCFs and 7.5% iron Magnetic Nanoparticles (MNPs)—Fe₄O₃ were used in the discrete ascending cycles of recycling, focusing on the surface quality performance optimization of the printed parts. Through stereoscopy evaluation, under-extrusion, and over-extrusion defects, as well as non-uniform material flow, are assessed in order to first investigate the influence of various process parameters’ application on the printing quality of each material and, second, to analyze the optimal value fluctuation of the printing parameters throughout the recycling cycles of the materials. The results indicate that after applying certain adjustments to the main printing parameter values, the examined recycled reinforced materials are still effectively 3D printed even after multiple cycles of recycling. A morphology examination using scanning electron microscope (SEM) revealed surface alterations, while a cytotoxicity assessment revealed the adverse effects of both materials in the form of cell viability and the release of proinflammatory cytokines in the cell culture medium.