Experimental Study of Effect of Infill Density on Tensile and Compressive Behaviors of Poly Lactic Acid (PLA) Prepered by 3D Printed (FDM)

Abstract

One of the most advanced production techniques in the manufacturing sector is the Additive Manufacturing Process (AMP), commonly known as 3D printing. Among its various methods, Fused Deposition Modeling (FDM) is widely used for fabricating intricate geometries. Unlike CNC machining, injection molding, and sculpting techniques, which typically generate 70%-90% material waste, FDM is a more efficient process that significantly minimizes material loss. This study examines the impact of infill density on the tensile and compressive behavior of Poly Lactic Acid (PLA), as well as its mechanical and fracture properties. The research focuses on a hexagonal infill pattern with varying infill percentages of 25%, 50%, 75%, and 100%. In additive manufacturing (AM), prismatic closed-cell structures, commonly known as honeycomb infill, are frequently used to enhance the mechanical integrity of printed parts due to their uniform density and periodic nature. Additionally, the study evaluates the effect of print orientation at 0°, 45°, and 90°. The ASTM D638 standard was followed in designing the tensile test specimens. The findings indicate that tensile strength and elastic modulus increase with higher infill density. While variations in print orientation (0°, 45°, and 90°) result in only slight changes in tensile strength and elastic modulus, an increase in infill density reduces elongation at break. Furthermore, increasing the infill density also leads to higher compressive strength, demonstrating a direct correlation between structural integrity and material distribution in FDM-printed PLA components.