(603d) Engineering Filament Design for Enhanced Printability and Mechanical Properties of Additively Manufactured Plastic Parts

3D printing enables the net shape manufacturing of objects with minimal material waste and low tooling costs, but the functionality and performance of these objects is generally limited. One of the most common 3D printing technologies and the primary consumer-user technology is fused filament fabrication (FFF), which relies on the extrusion of thermoplastic filaments through a heated nozzle. The melted filament is pushed through the nozzle by plunger action of the unheated filament. The object of interest is built up layer-by-layer as the nozzle is translated in the x-y plane. These 3D printed parts tend to suffer from poor mechanical properties due to weak interlayer interfaces that develop during the printing. There is generally an intrinsic trade-off between part accuracy and mechanical properties, where higher temperatures tend to enhance diffusion of polymer chains across the interfaces but this also tends to allow the material to flow which distorts the shape. Here we discuss routes to manipulate these trade-offs through structured core-shell filaments. Routes to produce parts with less warp (deformation) and improved mechanical properties will be discussed. Finally, we will briefly discuss how the shape of the object affects these properties and the importance of the tool path to obtain desired properties.