materials Article Towards Distributed Recycling with Additive Manufacturing of PET Flake Feedstocks Helen A. Little 1, Nagendra G. Tanikella 2, Matthew J. Reich 2, Matthew J. Fiedler 1, Samantha L. Snabes 1 and Joshua M. Pearce 2,3,4,* 1 re:3D Inc., 1100 Hercules STE 220, Houston, TX 77058, USA;
[email protected] (H.A.L.);
[email protected] (M.J.F.);
[email protected] (S.L.S.) 2 Department of Material Science and Engineering, Michigan Technological University, Houghton, MI 49931, USA;
[email protected] (N.G.T.);
[email protected] (M.J.R.) 3 Department of Electrical and Computer Engineering, Michigan Technological University, Houghton, MI 49931, USA 4 Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University, 00076 Espoo, Finland * Correspondence:
[email protected]; Tel.: +1-906-487-1466 Received: 28 July 2020; Accepted: 22 September 2020; Published: 25 September 2020 Abstract: This study explores the potential to reach a circular economy for post-consumer Recycled Polyethylene Terephthalate (rPET) packaging and bottles by using it as a Distributed Recycling for Additive Manufacturing (DRAM) feedstock. Specifically, for the first time, rPET water bottle flake is processed using only an open source toolchain with Fused Particle Fabrication (FPF) or Fused Granular Fabrication (FGF) processing rather than first converting it to filament. In this study, first the impact of granulation, sifting, and heating (and their sequential combination) is quantified on the shape and size distribution of the rPET flakes. Then 3D printing tests were performed on the rPET flake with two different feed systems: an external feeder and feed tube augmented with a motorized auger screw, and an extruder-mounted hopper that enables direct 3D printing.