(i) The model assumes an isotropic pressure, therefore does not account for the anisotropic pressure along axial or radial directions.(ii) It considers only a liquid and a solid phase and does not account for secondary phases resulting from the reaction between liquid and powder.(iii) The geometrical assumptions are applicable for densities below 90–92% (initial/intermediate sintering stages), according to the LPS model by Kingery et al where there is no formation of closed porosity[40,41].