Session: 02-07-01: Design for AM and Sustainability

Paper Number: 163970

Effects of Infill Density and Raster Angle on Additively Manufactured PLA and PETG Polymers Using the Grid Infill Pattern 

Additive manufacturing (AM) is a manufacturing method that fabricates parts in a layer-by-layer process. AM has gained popularity due to its inherent ability to create less material waste. However, the layer-by-layer manufacturing process generates parts with properties that are challenging to predict. This anisotropic nature results from the different directions and printing parameters in which parts can be manufactured. This research aims to advance the understanding of the mechanical behavior of additively manufactured parts. To accomplish this, mechanical test samples were manufactured using material extrusion and tested in tension according to ASTM standards. Material extrusion is defined as an additive manufacturing process in which material is selectively dispensed through a nozzle or orifice according to ASTM standards. The tensile tests were performed on an 800 Series Universal Tensile Tester by Test Resources. The variables modified during testing were the infill density and raster angle. Infill density is a measure of how much internal volume of a solid is printed; this can be decreased to save money on material. However, the strength of the part will decrease. The raster angle is the angle at which the infill was printed. The infill density varied incrementally between 25%, 50%, 75%, and 100%, while the raster angle varied between 0°-90°, 30°-60°, and 45°-45°. For each of these specimens, the effect of raster angle and infill density was studied and compared to identify optimal tradeoffs between the mechanical properties and different material parameters. Preliminary testing showed that as the infill density increased, the Young’s Modulus and Ultimate Tensile Strength also increased. There was an optimal range in some samples where the 75% infill density and 100% infill density did not show a great difference. This is significant because under certain conditions and applications, the infill density can be decreased to 75% or even lower to maintain mechanical properties and save on material cost and component weight. The 45°-45° raster angle showed the highest Young’s Modulus and Ultimate Tensile Strength. Additionally, the changes in raster angle did not show significant differences between the mechanical properties. This is important because the raster angle can be altered without significantly degrading the mechanical behavior. The results of these experiments will provide engineers with a valuable tool for analyzing parts prior to manufacture, thereby enhancing the efficiency and reliability of the manufacturing process. This will be paramount in understanding how tradeoffs in infill density and raster angle can be used to create parts that are optimized for certain applications. 

Presenting Author: Edgar Bryant Kennesaw State University

Presenting Author Biography: My name is Edgar Bryant, I am a graduate student attending Kennesaw State University (KSU), pursuing a Ph.D. in Interdisciplinary Engineering with a concentration in Innovative Materials. I am passionate about the field of additive manufacturing with a strong interest in nuclear additive materials. My further goals are to further my knowledge and research through attending and participating in conferences. Presently I plan to be participating in my Graduate Engineering Minority (GEM) fellowship at Idaho National Laboratory working on complex AM fuel forms, with a goal of publishing papers. Through my ongoing and future efforts, I hope to leave a lasting impact on the world of engineering.

Authors:

Aaron Adams Kennesaw State University
Edgar Bryant Kennesaw State University
Mechack Nduwa Kennesaw State University
Cameron Coates Kennesaw State University
David Stollberg Kennesaw State University