Mechanical and antibacterial properties of FDM additively manufactured PLA parts

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.

Keywords

• Antibacterial copper nanoparticles
• Polylactic acid
• Fused deposition modelling
• Laser ablation in liquid
• Additive manufacturing
• E.coli