When GNP incorporated to HPLA, ∆W boxes moved almost entirely above the zero line, showing a general trend of over-extrusion in the printing of HPLA/GNP, and this over-extrusion is correlated with GNP content. It is noteworthy that all HPLA/GNP samples were successfully printed under various conditions, with varying degrees of quality. This is consistent with the reduced viscosity of HPLA/GNP nanocomposites resulted from the lubricating effect of GNPs and in addition to the better thermal stability. In case of LPLA, when NC incorporated ∆W boxes shifted to negative values. Although LPLA/NC samples have lower viscosity and better thermal stability compared to HPLA/NC and HPLA/GNP still 25% of the LPLA/NC samples failed to print. When GNP introduced to the LPLA samples, the variation of the ∆W boxes increased but the majority of the samples exhibited over-extrusion due to a lubricating effect of GNP.