Mechanical and antibacterial properties of FDM additively manufactured PLA parts
Anesu Nyabadza, L. M. Mc Donough, Arul Manikandan, Abhishek Basu Ray, Anouk Plouze, Corné Muilwijk, Brian Freeland, Mercedes Vázquez, Dermot Brabazon
Abstract
This study explores the compression and antibacterial properties of 10x10 × 10 mm polylactic acid (PLA) cubes manufactured through FDM additive printing for biomedical parts. A 3x3 full factorial DOE with 3 replicates examines the impact of printing parameters (infill %, print speed, and layer height). The highest compression strength and stiffness recorded were 91 MPa and 0.76 GPa, respectively. Despite minor mass variations (1.05 ± 0.09 g) under all the investigated parameters, the mean strength of all printed parts was 67.6 ± 10.6 MPa, highlighting the significant influence of processing parameters on mechanical properties. Heat treatment at 60 °C for 30 min improved stiffness. Investigation of various parameters, including layer height and orientation, revealed that larger layer heights resulted in reduced compression strength. Anisotropic compression properties persisted post-heat treatment due to thermal stresses and interlayer bonding. The flat direction (top view) exhibited higher compression properties due to a homogeneous microstructure, minimized interlayer bonding impact, and increased crystallinity. Antibacterial properties against E.coli were induced via coating with peanut-shaped copper nanoparticles (68–267 nm). Nanoparticles were fabricated via a combination of wet chemistry and laser ablation.