SLS Layer Adhesion
Selective laser sintering prints layer by layer, just like SLA and FDM. However, here the particles are fused in all directions. This gives SLS prints isotropic properties, and also one of the main reason that it achieves such excellent mechanical properties, when compared to other 3d printing methods.
Comparatively, adding a composite, like glass, can make the structure anisotropic, stretching out the structure. This usually results in the model being weaker in the build direction.