Session: 15-01-01: ASME International Undergraduate Research and Design Exposition

Paper Number: 150145

150145 - Testing of Additively Manufactured High Impact Polystyrene (Hips) Tensile Specimens 

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 anisotropic nature of parts created using AM. To accomplish this, tensile test samples of High Impact Polystyrene (HIPS) were manufactured using material extrusion and tested in tension according to ASTM standards. The HIPS material is supplied through Matter Hackers. 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 be decreased. The raster angle is the angle at which the infill was printed. The infill density varied incrementally between 5%, 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 will be studied and compared to identify optimal tradeoffs between tensile strength and different material parameters. The tensile tests were performed on an 800 Series Universal Tensile Tester by Test Resources. Preliminary testing showed that a printing combination of 100% infill density and a raster angle of 30°-60° displayed the highest Young’s Modulus at 207,380 psi. In addition to the physical testing, computer-aided engineering simulations will also be conducted using Ansys. These simulations will be compared and tested for accuracy against the physical tests. The results of this research will provide engineers with a valuable tool for analyzing parts prior to manufacture, thereby enhancing the efficiency and reliability of the manufacturing process. Initial testing using computer-aided modeling software shows a convergence with the physical AM specimens. However, the convergence widens when the infill density is less than 100%. This part of the research aims to create a more applicable method of predicting the anisotropic nature of AM samples through computational modeling. For example, if the infill density is decreased, the tradeoff in strength would be better predicted during the design of a product. 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, and I am an undergraduate student attending Kennesaw State University (KSU). I am working on completing my bachelor's degree in Mechanical Engineering Technology with a minor in Manufacturing Engineering. I have a deep interest in the field of additive manufacturing, and my goal is to further my knowledge and research through a doctoral program. Upon completion of my bachelor's degree, I plan on staying at KSU to complete a PhD in Interdisciplinary Engineering with a concentration in Innovative Materials.

Authors:

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