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Description
Advancement in Additive Manufacturing (AM) technologies relieved many design and realization limitations and allowed for novel solutions, which was, in some cases, non- manufacturable using traditional machining practices. AM has been pivotal in the area of prototyping ubiquitously in every market sector, however prototypes were a mere resemblance to traditionally manufactured products. As AM technologies improved to leverage the properties of nearly every class of engineering material, the production time, reliability, and repeatability also improved. Of available AM processes, Fused Deposition Modeling (FDM) occupies a sizable market share due to its simplicity and scalability. Some shortcomings of FDM, and arguably all AM, are the suboptimal physical and mechanical properties of finished parts in comparison to their traditionally manufactured counterparts. The objective of this research is to use FDM to create a multi-functional structure using acrylonitrile butadiene styrene (ABS) without compromising the mechanical or physical properties. In addition to loading bearing ability, the ABS 3D-printed structure is designed for concurrent fluid transfer and electric connectivity to achieve multifunctionality. The approach to accomplish this objective is to additively manufacture 10 mm OD and 4 mm ID tubes with different geometrical complexity such a straight tube, 90o bend, and two orthogonal 90o bends. The tubes were internally sealed with Smooth-On XTC-3D in preparation for the metallization process. The sealing process yielded tubes that were able to withstand at least 30 psi. Once the internal surfaces were sealed, they were functionalized for silver coating in a two-step process. First, the surfaces were cleaned using an organic solvent to remove organic contaminates and residuals from the sealing process. Second, the internal surfaces were treated with nitric acid to activate the free radicals which promotes adhesion. The surfaces were then metallized by flowing a mixture of dextrose and silver nitrate solutions for six minutes, which resulted in a silver coating deposition of 0.253 μm. Optical, mechanical, and electrical characterization protocol was carried out to elucidate the effects of the sealing and coating processes on the behavior of FDM-manufactured structures. The finalized process was applied and tested successfully on an FDM cube satellite test structure.
