Surface Degradation of Additively Manufactured ABS for Naval Applications

Additive manufacturing (AM) has played a great part in the manufacturing process of several industries due to its rare shape-making ability that can optimize the creation of parts. Within the marine industry, the application of AM is confined due to the remaining questions regarding the degradation of polymers in a saline environment and whether AM is more viable than its traditional manufacture (TM) counterpart. In this work, the surface degradation of AM and TM ABS samples is analyzed in a simulated marine environment. The simulated environment is created by having a set temperature of 22°C, 27°C, and 105°C respectively where the samples are aged for a duration of 4, 8, and 16 days. The ABS material is molded and cut into rectangle samples for comparison with its 3D printed counterpart. Surface tests are conducted using a DektakXT profiler testing machine to measure the degradation of the surface roughness of each sample. Microindentaion tests will be done to show determine the average elastic modulus of the ABS samples. This research will help with the widespread adoption of AM ABS in the naval industry as well as provide information regarding the viability of AM in a corrosive environment.

Hello, my name is Daniel Hernandez. I am a rising junior mechanical engineering student, here at GMU. This summer I had the privilege of working with Ali Beheshti on the surface degradation of additively manufactured ABS for naval applications. Additive manufacturing is a disruptive technology that has become a forefront in many industries due to its ability to create virtually any geometrical 3D structure at exceptional quality. There are various forms of additive manufacturing and materials that can be used in the manufacturing of a product. A range of materials from metals to ceramics can be used in the additive manufacturing process, however, polymers such as ABS and PLA are the optimal choice given their excellent durability, strength, and thermal resistance. Many of the current additive manufacturing processes involve adding successive layers of material on top of each other vertically until the object is created. This creative form of production has opened the door for endless possibilities in many industries. As revealed by the medical industry additive manufacturing has been used to create more realistic and affordable casts and prosthetics. Where there has even been a success in research studies in additively producing organs such as a small-scale functioning heart. Currently, in terms of additive manufacturing in the naval application, many polymers have been used for surface-ship repairs and recreation of existing ship parts. Naval Sea Systems Control, a system that is responsible for the design, deliverance, and maintenance of ships for the US Navy, currently uses additive manufacturing for the replacement of equipment knobs and door bolts. However, for the use of additive manufactured parts for at sea application the usage is rather selective due to the significant design factors the corrosive environment, and high temperatures the ocean imposes on marine components. The questions that were aimed to be answered by this project are: To what degree does the surface of additively manufactured and traditionally manufactured ABS polymers degrade in a simulated saline environment? and how viable is additively manufactured ABS polymers in a saline environment in comparison to its traditionally manufactured counterpart? Studies have shown after extensive exposure to the marine environment the cross-section of the additively manufactured polymers stayed intact and showed little to no degradation rather the polymers were shown to chemically break down layer by layer starting at the surface due to water exposure. Resulting in the formation of pores, indents, and film lines. Based on a similar experiment done by the University of Alabama, an aging process was modeled to expose ABS samples to a simulated saline environment. Where sets of samples are to be submerged for 4,8, and 16 days in varying temperatures. Tanks, artificial seawater, and heating equipment were ordered in preparation for the submergence of the polymers. Rectangular ABS samples were modeled through the use of CAD inventor and were fabricated through the use of fusion deposition modeling. Following this traditionally manufactured ABS samples were ordered from a plastic manufacturer. Although we were unable to start the experimental or aging phase of the project this semester it is our hope to carry on the project in the spring of 2021 to observe the change in mechanical strength, wear, and friction of the surfaces of the ABS polymers. Based on the outcomes of the degradation of other polymers in previous studies it is anticipated that the traditionally manufactured polymers will perform significantly better. Thank you!