Electroplating Polymer Based Additive Manufactured Parts for Enhanced Structural Performance

Abstract

Additive manufacturing has been adopted in many aerospace and defense applications to reduce weight and buy-to-fly ratios of low-volume high- complexity parts. Polymer-based additive manufacturing processes such as Fused Deposition Modeling (FDM) has enabled aerospace manufactures to improve the structural efficiency of parts through generative design or topology optimization. This level of design freedom did not exist in the past due to limitations associated with traditional manufacturing processes such as subtractive machining. Improvements in the material and the maturation of the FDM process has led to the production of many non-structural flightworthy parts used in aircraft today. Polymer-based additive manufacturing can be further leveraged in aerospace applications with the addition of electroplated coatings that act as reinforcement. While many of the commonly known electroplated coating applications involve enhancing the part appearance, electroplated coatings can also improve the strength, stiffness, and durability of plastic parts. Depending on the use case, the thickness of the metallic plating material (combination of copper and nickel) can be tailored to achieve the desired composite properties (metal and polymer). In this research, the tensile and flexural mechanical properties were assessed for Ultem™ 9085 FDM printed specimens and compared to specimens with metallic coating thicknesses of approximately 75-μm, 150-μm, and 300-μm. Non- destructive inspections using x-ray computed tomography were performed prior to mechanical testing to assess the electroplated coating thickness variation and overall quality.