Fusion Bonding Behavior of 3D Printed PA6/CF Composites Via Post Fabrication Compaction

Additive manufacturing (AM) is becoming a robust production technology for aerospace, healthcare, and construction industries among others. Fused Deposition Modelling (FDM) is one of the methods most used to 3D print products. FDM has limitation due to interlayer adhesion and restriction imposed by the printing direction. Specially with AM composites, as reinforced nylon PA6 with short fibers, parts show more strength along the direction of the filament due to the alignment of the carbon fibers, but weaker in other directions. The proposed method to solve this issue is to print parts separately and join them together by fusion bonding. PA6/CF dovetail and simple lap joint samples were designed to study the optimal procedure for fusion bonding using Talc Bed Compaction Molding (TBCM), and were tested using mechanical tensile testing processes, comparing tensile stress characteristics to the specifications provided by Desktop Metal and reference results from 3D printed, untreated samples. This analysis was used to test T-brackets designed with subparts printed in different directions, to verify the procedure was optimal. The results indicate that T-bracket configuration after using TBCM show an increase of strength and elongation of 144%. Also, TBCM can improve the internal structure quality in 3D printed parts, limit the number of voids, and create strong bonds between PA6/CF. This paper will discuss the optimal fusion bonding procedure and the bonding strength analysis of PA6/CF using TBCM