Â© 2018 Elsevier B.V. Fused Filament Fabrication (FFF) is the most popular additive manufacturing method because of its numerous capabilities and relatively low cost. This comes with a trade off as FFF printed parts are typically weak in the layer deposition direction due to insufficient interlayer bonding. This research adopts the method of cold plasma treatment and investigates the potential enhancement of interlayer bonding by altering the printed surface prior to the deposition of the next layer. Polylactic acid (PLA) is used as the printing material, due to its ubiquity in industry. The bonding strength is measured by the shear bond strength test. The results show that bond strength improved over 100% with 30 s of treatment and over 50% with 300 s of treatment. A mechanically polished surface is also included in the comparison for the high surface wettability, but the result shows no improvement. This indicates that wettability may not be the dominant mechanism for enhanced bonding after treatment.