Comparison of 3D Printed Underwater Propeller Using Polymers and Conventionally Developed AA6061

Additive manufacturing (AM) is an emerging technology for the rapid manufacturing of highly complex profiles. Polymers offer great opportunities for components and products meant to operate in seawater. In this work, UWP models were developed by PLA, Nylon 6, and ABS polymers, and Aluminum alloy 6061 (AA6061). Polymers were printed using fused deposition modeling and AA6061 was processed through cold forging. The complex profile of blades of UWP makes it more challenging as it has a twist and Omni-directional gradient, requiring several stages of manufacturing, intensive labor, and time in conventional manufacturing. Further, UWP is subjected to variable loads and harsh environments while it is expected to generate thrust to move the vehicle at the required speed. The stress analysis using the finite element method within the dimensional conformance of the 3D printed and conventionally made UWP reveals that all materials are safe. The pressure distribution is analyzed using the finite volume method-based pressure-velocity coupling algorithm (PIMPLE). Additive manufacturing has clear advantages while ABS emerges as the best material followed by Nylon 6, PLA, and AA6061. Though AM process imparts poorer mechanical and physical properties to the parts, still the results indicate that the computed maximum stresses are minimal. The degradation of the polymers in terms of percent mass loss, as well as their average surface roughness, was lower than the AA 6061.