Printability of recycled feedstock for extrusion additive manufacturing

The 3D printability of several thermoplastic feedstocks, recycled from post-industrial or post-consumer waste and the properties of printed items are presented and discussed. A preliminary investigation has been conducted with post-industrial scraps of PETG and PLA recycled into printable filaments. A comparison with samples produced with corresponding virgin materials showed similar mechanical characteristics. The printability of virgin, recycled and recycled/UVA exposed ABS pellets from extruded scraps is also compared. Recycled pellets were aged by exposure to UVA light up to 400 hours. The results of mechanical tests of 3D printed specimens indicate that the printability of recycled and artificially aged ABS pellets is still acceptable. Furthermore, nylon fibres recycled from clothing were used as feedstock for 3D printing. A simple and inexpensive recycling process is proposed to recover extruded pellets from nylon t-shirts. On the other hand, 3D printing tests showed that the recycled nylon has some prospects for 3D printing, but only if mixed at low percentage with virgin polymer.