Impact Fracture Resistance of Fused Deposition Models from Polylactic Acid with Respect to Infill Density and Sample Thickness

Fused deposition modeling (FDM) is widely employed in prototyping due to its cost-effectiveness, speed, and ability to produce detailed and functional prototypes using a variety of materials. Simultaneously, consideration for the use of biodegradable polymers and a general reduction in their usage while enhancing the production of polymer-based products is at the forefront of sustainable practices and environmental consciousness. This study investigates the impact fracture resistance of FDM models fabricated from Polylactic Acid (PLA), examining the influence of infill density (50% and 100% infill) and sample thickness (2 mm, 3 mm, and 5 mm). Optical microscopy, FTIR spectroscopy, and SEM analysis of PLA filament and fractured FDM PLA surfaces in impacted samples were conducted to ascertain the influence of process parameters on impact damage and failure mechanisms. The results indicate that a 100% infill profile with a 2 mm thickness should be avoided due to unpredictable behavior under impact. Conversely, a 5 mm thickness demonstrates significantly higher durability in comparison to a 50% infill profile. Optimal impact strength is observed in samples with a 3 mm thickness, suggesting potential material savings with 50% infill without compromising mechanical properties. The findings contribute valuable insights for refining FDM parameters and advancing the understanding of material behaviors in sustainable manufacturing practices.