Manufacturing of Metal–Polymer Hybrid Parts Using a Desktop 3-Axis Fused Filament Fabrication 3D-Printer

This study evaluated the manufacturing of metal–polymer hybrid parts using a 3-axis desktop Fused Filament Fabrication (FFF) printer. Two printing strategies were employed: a more trivial one, consisting of 3D-printing the polymer directly onto the metal surface, and an alternative one, consisting of encasing the metal with printed polymer. Materials used were Ti-6Al-4V (both rolled/sandblasted and 3D-printed by laser powder bed fusion) and polyamide-based polymers. Demonstrators were designed to resemble omega-shaped skin stringers commonly used in vehicular applications. Several challenges were addressed, including harvesting the heat emanating from the deposited polymer to locally increase the substrate temperature, as well as positioning the metallic parts to avoid undesired collisions during the print job. Furthermore, to better understand the behavior of the encased metal under load, pullout tests were conducted on commercially available M6 and M8 steel nuts that were enclosed in a 3D-printed composite block. Results revealed that the length of the edge shared by the enclosure and metal significantly impacted the pullout strength.