Novel design for an additively manufactured nozzle to produce tubular scaffolds via fused filament fabrication

Additive Manufacturing of scaffolds with controlled porosity has demonstrated its value in many fields such as tissue regeneration and filtration applications. However, there is a scarcity of reports investigating the manufacturing of scaffolds with hollow fibers. Mainly, this was due to the lack of proper tools (extrusion nozzles) that enable the production of such structures. In this study, a methodology for designing and manufacturing a nozzle that can be fitted onto a fused filament fabrication 3D printer is proposed. Titanium laser powder bed fusion technology, coupled with chemical polishing, was used to produce the complex design of the nozzle with minimal post processing steps. Through this approach, we were able to produce a nozzle with the required internal structure. Numerical simulations and experimental analyses were conducted to better understand the melt flow behavior within the nozzle and the extrudate swell. The designed nozzle was capable of extruding tubular fibers with an outer and inner diameter of 1.3 mm and 0.5 mm, respectively. This, for example, enables the fabrication of tissue regeneration scaffolds with hollow fibers. This proposed method for designing and manufacturing can be used to produce nozzles capable of 3D printing scaffolds that best suit the intended application.