Fabrication of suspended uniform polymer microfibers by FDM 3D printing

In this study, we propose a novel method to fabricate suspended polymer microfibers with the principle of liquid bridge in the range of 25–180 μm in thickness and centimeter range in length by stretching viscoelastic fluid, employing a commercial fused deposition modeling (FDM) 3D printer and a PLA (polylactic acid) 3D printing filament. Highly uniform thickness of microfibers (CV < 5%) is also achievable in various sizes by our proposed method in ranges of 25–30 μm and 75–130 μm. For the thickness control and the uniformity of the thickness, we investigate three main printing control factors (filament extrusion volume, printing speed, and gaps between printing nozzle and printing bed) through experiment. The observation from the experiment concludes that the filament extrusion volume is the most dominant factor to rule the thickness of the suspended polymer microfiber, and the printing speed is the following determinant factor. The uniformity of the thickness is maintained with a lower extrusion volume and a higher printing speed, and it is concluded that such a printing setting makes microfibers thinner due to smaller viscoelastic internal compressing force along the microfiber. Additionally, we analyze a relation of the three printing parameters to estimate the thickness of the microfiber by FDM 3D printing.