## 3 Results
### Analysis of the Mechanical Properties of the 3D-Printed Samples  
The 3D printing process followed after the filaments were assessed, in order to manufacture specimens and examine their mechanical behavior. The tensile test results are displayed in Figure 8. All of the specimens prepared, at all concentrations of the three distinct glass additive types, showed an improvement in tensile strength, according to Figure 8b. The PLA/Glass Beads specimens at a concentration of 9.0 wt.% showed a slight decrease compared to the other composites; still, their properties were marginally higher than the pure PLA polymer. The PLA/Glass Flakes composite with 6.0 wt.% concentration revealed the highest value of 56.7 MPa out of all the samples tested, which was 33.8% higher than the sample composed of PLA. Figure 8c shows a similar pattern for the modulus of elasticity, with all samples exhibiting an increase in value aside from the PLA/Glass Beads specimen with a concentration of 9.0 wt.%, which once more exhibited a minor decline. The sample with the highest elasticity modulus, which was 24.3% higher than that of pure PLA and contained glass beads, was that with a concentration of 3.0 weight percent. Figure 8: Tensile test results for all 3D-Printed samples: (**a**) graphs illustrating the relationship between tensile stress and calculated strain from one randomly selected 3D-printed specimen for each composite, (**b**) tensile strength results, and (**c**) tensile modulus of elasticity results. Each compound is presented in a different color according to the legend below the graphs. Figure 9 shows the values of the flexural properties as they were derived in the corresponding tests. According to the ASTM D790-10 standard, the average flexural strength values were calculated at a maximum strain of 5% since no failure occurred at the specimens up to this stain. The reinforcement of the flexural characteristics was significantly improved by the addition of glass particles to the PLA matrix, with all composites exhibiting higher values than those of the pure polymer. The maximum flexural strength value found at the PLA/Glass Beads composite at 3.0 wt.%, which was 108.8 MPa, i.e., 46.8% greater than the value for pure PLA (Figure 9b). The flexural modulus of elasticity followed a similar trend, with all composites containing glass additives showing enhanced mechanical responsiveness relative to the virgin polymeric matrix. In this instance, the PLA/Glass Powder combination with a 3.0 wt.% concentration achieved 3.32 GPa, reaching a 20.6% increase over that of pure PLA. The composite with 9.0 wt.% of glass flakes showed a minor decrease (Figure 9c). Figure 10 shows the specimens' impact strength, Vickers microhardness, tensile and flexural toughness, as well as the toughness calculated in the tensile tests for the filaments. Figure 10a demonstrates how the addition of all types of glass fillers (beads, flakes, and powder) at various concentrations affected the composites' impact strength. When compared to the pure PLA polymer, the mechanical response was improved at 3.0 and 6.0 wt.% concentrations of all three types of glass fillers. At 9.0 wt.% concentration, the impact strength was decreased. Compared to the pure polymer, PLA/Glass Flakes with 6.0 wt.% concentration showed an improvement of 23.6%. Figure 10b also shows that the Vickers microhardness results for all composites improved gradually as the concentration of the glass additives increased. The maximum value of 18.5 HV was measured in the PLA/Glass Powder with 9.0 wt.% loading. The stress-strain curves of the samples and filaments were integrated to get the tensile and flexural toughness values, which represent the energy absorbed by the materials  
Figure 9: Flexural test results for all 3D-printed samples: (**a**) graphs depicting the relationship between flexural stress and calculated strain from one randomly selected 3D-printed specimen for each composite. The experiment terminated at 5% strain, following the ASTM D790 standard instructions.