This paper presents the static mechanical behavior and the dynamic thermomechanical properties of four market-available reinforced and non-reinforced thermoplastics and photopolymer materials used as precursors in different additive manufacturing technologies. This article proposes a characterization approach to further address development of aeronautic secondary structures via 3D-printed composite materials replacing conventional manufactured carbon fiber reinforced polymer (CFRP) composites. Different 3D printing materials, technologies, printing directions, and parameters were investigated. Experimental results showed that carbon-reinforced ONYX_R material exhibits a transition point at 114 °C, a 600 MPa tensile strength, and an average tensile strain of 2.5%, comparable with conventional CFRP composites manufactured via autoclave, making it a suitable candidate for replacing CFRP composites, in the aim of taking advantage of 3D printing technologies. ONYX material exhibits higher stiffness than Acrylonitrile-Butadiene-Styrene Copolymer (ABS), or conventional Nylon 6/6 polyamide, the flexural modulus being 2.5 GPa; nevertheless, the 27 °C determined transition temperature limits its stability at higher temperature. Daylight High Tensile (further called HTS) resin exhibits a tensile strength and strain increase when shifting the printing direction from transversal to longitudinal, while no effect was observed in HighTemp DL400 resin (further called HTP).

Laser Powder Directed Energy Deposition (LP-DED) is an advanced additive manufacturing process that uses a focused laser beam to melt and fuse powder material onto a substrate. This technology enables the production of complex metal components with high precision and material efficiency. The properties of the powder feedstock are highly important and have been extensively studied in the literature. Powder size distribution and particle shape have been identified as key factors influencing the flowability, and it is imperative that nozzle designs take these into account for optimum material delivery. The laser–powder interaction, where the laser energy influences the melting behavior, as well as nozzle designs, have been highlighted in both historical and the more recent laser cladding literature. Finally, a comprehensive analysis of fluid dynamic simulations of the powder particles and their interaction with the nozzle design is provided.

Materiale Plastice - a peer-reviewed scientific journal,specialised in the field of chemistry, polymers, elastomers and plastics research

This study investigates how laser power–scan speed combinations influence densification, surface quality, and mechanical performance of Ti-6Al-4V parts fabricated by Powder Bed Fusion–Laser Beam/Metal (PBF-LB/M) on a DMG MORI LASERTEC 30 SLM (2nd generation) system. A parametric matrix was explored by varying laser power (150–400 W) and scan speed (0.9–1.4 m·s⁻¹) at constant layer thickness and hatch spacing, deliberately omitting contour exposure to isolate core scan effects. A stable processing window was identified (250–300 W; 0.9–1.0 m·s⁻¹) corresponding to ~50–60 J·mm⁻³ volumetric energy density (VED) achieved at 99.5% with residual porosity of 0.1–0.3%. In this regime, as-built roughness measured Ra = 4–6 µm on top surfaces and Ra = 15–17 µm on side surfaces. Mechanical testing in the as-built showed ultimate tensile strength (UTS) = 1150–1180 MPa and offset yield strength (YS_0.2) = 955–994 MPa, with elongation up to 6.7%. Hardness increased from 220 HV to 360 HV as densification improved. Notably, similar VED values derived from distinct power–speed combinations resulted in divergent outcomes, confirming that VED alone does not uniquely predict quality. Comparative benchmarks from the literature data highlight the performance achieved. The resulting process–property map provides a practical reference for parameter optimization, reproducibility evaluation, and transferability across platforms.

Materiale Plastice - a peer-reviewed scientific journal,specialised in the field of chemistry, polymers, elastomers and plastics research

Lattice structures are increasingly used in lightweight engineering applications, particularly in the aerospace, biomedical, and automotive sectors. However, their limited stiffness and narrow linear elastic region can restrict their use in load-bearing applications. This study investigates a hybrid design strategy for improving the compressive performance of Ti-6Al-4V octet lattice structures generated in polar coordinates. Hybrid lattices incorporating a 0.5 mm outer and inner tubular shell and reference lattices without a shell were designed using implicit modeling techniques and manufactured by laser powder bed fusion (LPBF). The mechanical response was characterized through uniaxial compression testing showing an increase in the compressive strength of 900 to 1000% and a strength-to-weight ratio similar to that of bulk titanium in the case of the hybrid samples. Geometrical analysis revealed systematic manufacturing deviations, with all lattice struts exhibiting larger diameters than their nominal dimensions. The hybrid design significantly increased the compressive modulus and yield strength while introducing a moderate increase in mass. Furthermore, the as-printed quality of the polar-generated lattices followed trends reported for equivalent Cartesian-coordinate lattice structures or produced even better results. Overall, the results demonstrate that hybridization can increase compressive strength and modulus significantly while improving the strength-to-weight ratio, with polar lattices exhibiting geometry-dependent trends consistent with Cartesian structures and curved-cell designs providing more uniform volume filling and improved suitability for axisymmetric components.