Publications

The objective of this research was to find a relationship between the microstructural and macrostructural properties of polylactic acid, acrylonitrile butadiene styrene and polyamide 12 (PA12) when processed using fused deposition modelling. The crystallinity, enthalpy of crystallization (ΔHc), glass transition temperature (Tg) and Young's modulus (E) were evaluated. The results showed that crystallinity increased for all materials after the 3D printing process, leading to an increase in ΔHcand a decrease in Tg, particularly in PA12. This variation in microstructural properties resulted in a significant decrease in Young's modulus, indicating a reduction in the stiffness of the printed materials. The research suggests that an increase in crystalline material volume, resulting from polymer chain rearrangement during 3D printing, reduces the energy required for thermal softening and decreases the material's rigidity. © The Author(s) 2025

In additive manufacturing (also known as 3D printing), a layer-by-layer buildup process is used for manufacturing parts. Modern laser 3D printers can work with various materials including metal powders. In particular, mixing various-sized spherical powders of titanium alloys is considered most promising for the aerospace industry. To achieve desired mechanical properties of the final product, it is necessary to maintain a certain proportional ratio between different powder fractions. In this paper, a modeling approach for filling up a rectangular 3D volume by unequal spheres in a layer-by-layer manner is proposed. A relative number of spheres of a given radius (relative frequency) are known and have to be fulfilled in the final packing. A fast heuristic has been developed to solve this special packing problem. Numerical results are compared with experimental findings for titanium alloy spherical powders. The relative frequencies obtained by using the imposed algorithm are very close to those obtained by the experiment. This provides an opportunity for using a cheap numerical modeling instead of expensive experimental study. © Springer Nature