A novel method and printhead for 3D printing combined nano-/microfiber solid structures
Yahya Kara, Norbert Krisztián Kovács, Péter Nagy-György, Róbert Boros, Kolos Molnár
Abstract
In this study, we demonstrate a novel 3D printing method and printhead capable of 3D printing objects, which are combinations of nano-/microfibers and solid or infill layers. The method is a unique combination of material extrusion and melt-blowing: the filament can be fused and then either deposited or turned into ultrafine fiber mats with the aid of hot pressurized air. This study introduces the operation of the prototype device, the computational fluid dynamics (CFD) simulations of the airflow field, and various tests on the generated specimens. We were able to make layers of ultrafine fiber mats from poly lactic acid (PLA), which adhered to the solid deposited layers of the same PLA material. Higher air speed and smaller nozzle size resulted in smaller fibers. Fibers with a diameter of as small as 300 nm and an average of 900 ± 100 nm were generated at supersonic air velocities. The fiber layers enhance the crystallinity of the printed products, and can reinforce those. We can control the position and ratio of the fibers and the solid (or infill) parts of the printed object, so even porous objects can be generated. These hierarchical 3D printed objects have lots of possible applications, such as scaffolds, controlled drug delivery devices, filter media, structural composites and smart textiles.