Session: ASME Undergraduate Student Design Expo

Paper Number: 165514

Comparison of Mechanical and Tribological Properties in Pristine vs. Environmentally Degraded Additively Manufactured and Molded Polymers 

This study investigates the impact of environmental degradation on the mechanical and tribological properties of polymers fabricated through additive manufacturing and molding. Specifically, the research examines hardness, flexural strength, scratch behavior, and surface roughness of Acrylonitrile Butadiene Styrene (ABS) and Polyethylene Terephthalate Glycol (PETG) samples produced using both 3D printing and molding techniques.

To simulate environmental aging, samples were subjected to UV radiation and moisture exposure for 0, 300, 600, and 1200 hours following ASTM G154 standards. Mechanical properties were evaluated using ASTM D790 for flexural strength and ASTM D785 for hardness. Abrasion resistance and surface roughness were assessed using a Keyence digital optical microscope, and scratch behavior was examined following ISO 1518 standards using a TABER Reciprocating Abraser (Model 5900). A Leco LCR-500 hardness tester was utilized for hardness measurements, while flexural testing was conducted using a Mark-10 ESM303 Motorized Test Stand.

Preliminary results indicate significant differences in mechanical performance between 3D printed and molded samples, as well as between pristine and degraded samples. Scratch tests on 3D printed ABS samples showed an average removed volume of 8.77 ± 0.47 mm³/mm, whereas 3D printed PETG samples exhibited a lower average removed volume of 7.14 ± 0.39 mm³/mm. Hardness tests demonstrated that 3D printed ABS samples had a hardness of 87 ± 1.1 HRR, while molded ABS samples exhibited a slightly higher hardness of 90 ± 1.6 HRR. PETG samples displayed a more pronounced difference, with 3D printed samples measuring 86 ± 1.3 HRR, compared to 101 ± 4.7 HRR for molded PETG. These results suggest that molding processes generally enhance mechanical properties compared to additive manufacturing, with molded PETG anticipated to exhibit the highest durability among the tested materials.

The relationship between hardness, scratch resistance, and surface roughness is crucial in assessing the long-term durability of these polymers. Hardness directly impacts scratch resistance, as harder materials generally experience lower material loss under abrasive conditions. However, surface roughness also plays a significant role, as increased roughness can elevate friction and accelerate wear. By analyzing these factors together, a more comprehensive understanding of polymer degradation under environmental exposure can be achieved. Additionally, comparing these properties with flexural strength will help determine their effectiveness as indicators of overall material performance and durability in outdoor conditions. The findings could support material selection for applications requiring resistance to mechanical wear and environmental aging, particularly in industries relying on cost-effective, on-demand polymer manufacturing processes.

Presenting Author: Zachary Rehg Mercer University

Presenting Author Biography: Senior at Mercer University pursuing B.S. in Mechanical Engineering

Authors:

Alex Patrick Mercer University
Zachary Rehg Mercer University
Ronald White Mercer University
Jin Choi Mercer University
Caleb Luo-Gardner Mercer University
Michael Norenberg Mercer University
Arash Afshar Mercer University
Stephen Hill Mercer University
Dorina Mihut Mercer University