## 3 Results
### Analysis of the Morphology of the 3D-Printed Specimens  
SEM imaging was used to investigate the fragmentation and side surfaces of the 3D-printed specimens in order to evaluate their morphology. Images of the side surfaces of three tensile test samples, each made up of one of the three types of glass used in this study--PLA/Glass Beads 3.0 wt.%, PLA/Glass Flakes 3.0 wt.%, and PLA/Glass Powder 3.0 wt.%--are shown in Figure 11. Figure 11a,d, and g illustrate pictures of the samples' side surfaces at a magnification of 150\(\times\). Small defects in the layer fusion can be seen in the images. Specifically, in the case of the PLA/Glass Beads 3.0 wt.% sample (Figure 11a), the layer interfusion is not flawless. These flaws can be related to the possibility that the fillers in the matrix have saturated, which will affect how easily the material can be processed during 3D printing [52]. SEM pictures of the fracture surfaces of the tested composites' tensile specimens, captured at a magnification of 30\(\times\), are shown in Figure 11b,e,h. The photos do not display considerable deformation, suggesting a mostly brittle fracture mechanism. Images at a greater magnification of 300\(\times\) were used to undertake a more thorough inspection of the broken surface (Figure 11c,f,i). There were no agglomerations visible at this degree of magnification. Noteworthy is the presence of glass beads in Figure 11c. Figure 11: SEM pictures for **(a)** side surface of PLA/Glass Beads 3.0 wt.% specimen at 150\(\times\) magnification, **(b)** fracture surface of PLA/Glass Beads 3.0 wt.% specimen at 30\(\times\) magnification, **(c)** fracture surface of PLA/Glass Beads 3.0 wt.% specimen at 300\(\times\) magnification, **(d)** side surface of PLA/Glass Flakes 3.0 wt.% specimen at 150\(\times\) magnification, **(e)** fracture surface of PLA/Glass Flakes 3.0 wt.% specimen at 30\(\times\) magnification, **(f)** fracture surface of PLA/Glass Flakes 3.0 wt.% specimen at 300\(\times\) magnification, **(g)** side surface of PLA/Glass Powder 3.0 wt.% specimen at 150\(\times\) magnification, **(h)** fracture surface of PLA/Glass Powder 3.0 wt.% specimen at 30\(\times\) magnification, and **(i)** fracture surface of PLA/Glass Powder 3.0 wt.% specimen at 300\(\times\) magnification. The specimens with 6.0 wt.% of the three types of glass filler underwent the same investigation process. As shown in Figure 12a,d,g, the side surfaces were initially inspected using SEM images at a magnification of 150\(\times\). In this instance, the photos reveal that all specimens demonstrate flawless layer interfusion without any flaws or voids. However, the layer shape does not appear to be uniform across the specimens. Micro-voids and micro-porosity were discovered when the fracture surface was examined at a magnification of 30\(\times\), especially in specimens of PLA/Glass Beads 6.0 wt.% (Figure 12b). These findings suggest evidence of moisture absorption in the specimens [69; 70]. Micro-voids were found in the sample of PLA/Glass Flakes 6.0 wt.% (Figure 12e), primarily in the vicinity of the specimen's margins. Even when employing a 100% infill ratio, these micro-voids in the 3D-printed structure are acceptable because they result from the MEX 3D printing technique used to build the object layer [71]. A more ductile behavior is discovered after scrutinizing the sample using SEM pictures at 300\(\times\) (Figure 12c,i), and 150\(\times\) (Figure 12f) magnification levels. In the fracture sites, deformation is evident. Finally, both lateral and fracture surface investigations were performed on the specimens with a 9.0 wt.% concentration of each type of glass filler. The images were captured at 150\(\times\) magnification. The images depict that the samples of PLA/Glass Beads and PLA/Glass Flakes demonstrate faultless layer diffusion with no flaws or cavities.