Experimental Characterization of the Mechanical Properties of 3D Printed Structures with Polylactic Acid

Additive manufacturing, also known as 3D printing, has significantly transformed the manufacturing industry by offering cost-effective, rapid, and versatile production methods. Fused Deposition Modeling (FDM), also referred to as Fused Filament Fabrication (FFF), is among the most widely used additive manufacturing techniques, particularly for processing a broad range of thermoplastics. Key printing parameters in FDM such as infill density, print orientation, and layer thickness play a critical role in determining the mechanical properties of printed structure. Polylactic acid (PLA) is one of the most extensively used biodegradable thermoplastics for FDM printing due to its ease of processing and environmental benefits. While pure PLA is dielectric, the incorporation of conductive nanomaterials such as carbon black, significantly enhances its electrical conductivity. This study investigates the influence of 3D printing parameters on the mechanical properties of structures printed with both pure PLA and conductive PLA composite containing carbon black. 3D printed samples with varying solid infill ratios of 15%, 45%, 75%, and 100% were tested under tensile loadings with two different strain rates. Results showed that increasing solid infill density from 15% to 100% led to notable improvement in ultimate tensile strength, rising from 36.9 ± 0.35 MPa to 55.7 ± 0.12 MPa. In addition, infill orientation was also found to have a significant impact on mechanical performance. In addition, while had a significant impact on mechanical properties. Furthermore, while the incorporation of carbon black improved the electrical properties, we found that it results in a reduction in mechanical properties compared to pure PLA. This study highlights the importance of optimized printing parameters and material composition on the mechanical properties of FDM printed structures.