2.2. Samples Preparation

Different 3D-printing pattern architectures were tested to study their influence on the cross-sectional morphology and mechanical properties of the samples, according to Figure 1.

The internal architecture used for the 3D printing of the samples: (a). solid, (b). cylinder (tube), (c). standard.

The specifics of the samples were:

Plain walls with 0.5 mm thickness were printed to encase these samples;

Plain walls with 0.5 mm thickness were printed to encase these samples.

From each variant presented in Figure 1, five samples were obtained using a CreatBot DX - 3D double-nozzle printer, using 0.4 mm printing resolution and a 0.2 mm layer resolution for performing each mechanical test. The type and dimensions of the samples were adapted to the tests as follows:

Tensile test samples: total length 160 mm, calibrated length 60 mm, thickness 3 mm, radius between the calibrated section and the fastening sections 76.29 mm, fastening section length 22.5 mm and 20 mm width;

Cylindrical blocks for compression tests: diameter 10 mm, height 15 mm;

Three point-bending samples: 160 mm length, 16 mm width and 3 mm height;

Impact energy (shock resistance) cubic samples: 15 mm in edge.

In order to eliminate uncertainly values, each mechanical test was replicated five times, and the average values for the mechanical strength of the prints are presented in the paper.