Mechanical Properties of Direct Waste Printing of Polylactic Acid with Universal Pellets Extruder: Comparison to Fused Filament Fabrication on Open-Source Desktop Three-Dimensional Printers

Abstract

Fused filament fabrication (FFF) is the most common and widespread additive manufacturing (AM) technique, but it requires the formation of filament. Fused granular fabrication (FGF), where plastic granules are directly three-dimensional (3D) printed, has become a promising technique for the AM technology. FGF could be a key driver to promote further greening of distributed recycling thanks to the reduced melt solidification steps and elimination of the filament extruder system. However, only large-scale FGF systems have been tested for technical and economic viability of recycling plastic materials. The objective of this work is to evaluate the performance of the FFF and FGF techniques in terms of technical and economical dimensions at the desktop 3D printing scale. Recycled and virgin polylactic acid material was studied by using five different types of recycling feedstocks: commercial filament, pellets, distributed filament, distributed pellets, and shredded waste. The results showed that the mechanical properties from the FGF technique using same configurations showed no statistical differences to FFF samples. Nevertheless, the granulometry could have an influence on the reproducibility of the samples, which explains that the critical factor in this technology is to assure the material input in the feeding system. In addition, FGF costs per kg of material were reduced to less than 1 e/kg compared with more than 20 e/kg for commercial recycled filament. These results are encouraging to foster FGF printer diffusion among heavy users of 3D printers because of reducing the cost associated to the filament fabrication while ensuring the technical quality. This indicates the possibility of a new type of 3D printing recycled plastic waste that is more likely to drive a circular economy and distributed recycling.

Open source high-temperature RepRap for 3-D printing heat-sterilizable PPE and other applications

“… Dual drive extruder gears will help in printing with carbon fiber materials. Uses FFF instead of FPF/FGF, the latter of which can make use of far less-costly feedstocks such as pellets [71] , [72] , [73] , [74] , [75] , [76] and is more easily adapted for recycled 3-D printing [77] , [78] , [79] , [80] , [81] . …”

Open-Source Grinding Machine for Compression Screw Manufacturing

“…Finally, applying what has been learned on the micro compression screw manufacturing machine, a dedicated machine for creating screws for filament extruders and industrial-sized pellet 3D printers will be created. This grinding device was able to successfully manufacture custom extrusion screws, which radically reduce the cost of one of the core components of desktop-sized open-source FPF 3D printers [85]. This ability will provide the maker community with access to low-cost screws, thereby benefiting the circular economy based on distributed recycling and additive manufacturing [43][44][45][46], regardless of whether it is home-based manufacturing or a more centralized form of distributed manufacturing (e.g., community based) [103].…”

“…These compression screws also impact the cost of commercial recyclebots (e.g., the filabot extruder screw costs $749 USD [84], which is approximately the cost of an entire open-source recyclebot). In addition, preliminary results for desktop-sized open-source FPF 3D printers are promising [85], but the ability for the printer to handle larger pellets is restricted because of the commercially-available small-scale compression screw designs. In order for DRAM to reach its fullest potential, a low-cost open-source method is needed to drive down the costs of compression screws for both FPF/FGF 3D printers and recyclebots.…”

Open Source High-Temperature RepRap for 3-D Printing Heat-Sterilizable PPE and Other Applications

“…4. Uses FFF instead of FPF/FGF, the latter of which can make use of far lesscostly feedstocks such as pellets [71][72][73][74][75][76] and is more easily adapted for recycled 3-D printing [77][78][79][80][81].…”