Filament Development for Laser Assisted FFF 3D Printing

The aim of this paper was to develop filaments which can be used for laser assisted fused filament fabrication (FFF) 3D printing in order to increase the inter-layer bonding strength of the printed part. The filaments were developed from the most commonly used filament materials, acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) with the addition of different polymer additives. After performing near infrared (NIR) absorption tests, graphite was selected for further development as it possesses excellent NIR absorption capabilities whilst resulting in consistent filaments’ diameter and being economically viable. A conventional FFF 3D printer was initially used to test the printability of the developed filaments. Afterwards, a fiber couple laser diode was integrated within the printing head to heat up the previously extruded layer. The produced filaments were used to 3D print specimens for shear and tensile testing. With the laser heating, an increase of 14.5% in the elastic modulus and an increase of 27.8% in the tensile strength of the printed parts were noticed. This showed that adding additives into filament materials for localized laser heating is an effective method of increasing the inter-layer bonding, and therefore, the overall strength and durability of FFF 3D printed parts.