Waste Plastic Direct Extrusion Hangprinter

Abstract

As the additive manufacturing industry grows, it is compounding the global plastic waste problem. Distributed recycling and additive manufacturing (DRAM) offers an economic solution to this challenge, but it has been relegated to either small-volume 3D printers (limiting waste recycling throughput) or expensive industrial machines (limiting accessibility and lateral scaling). To overcome these challenges, this paper provides proof-of-concept for a novel, open-source hybrid 3D printer that combines a low-cost hanging printer design with a compression-screw-based end-effector that allows for the direct extrusion of recycled plastic waste in large expandable printing volumes. Mechanical testing of the resultant prints from 100% waste plastic, however, showed that combining the challenges of non-uniform feedstocks and a heavy printhead for a hangprinter reduced the strength of the parts compared to fused filament fabrication. The preliminary results are technologically promising, however, and provide opportunities to improve on the open-source design to help process the volumes of waste plastic needed for DRAM to address the negative environmental impacts of global plastic use.

Hangprinter for large scale additive manufacturing using fused particle fabrication with recycled plastic and continuous feeding

“…Today's high-volume 3-D printers are expensive (e.g., The BOX Large by BLB Industries costs $298,000 [33] and even the open source offerings from re:3D of the Gigabot XLT cost $17,000 [34] . Recently, however, Petsiuk et al [35] demonstrated the potential to make a FGF/FPF large scale printer with a GigabotX extruder based on the open source cable driven Hangprinter concept [36] . This radically reduced the cost of large-scale printing below $5,000 and offers the potential to make an impact on GHG emissions be allowing large-scale recycled plastic waste printing at more accessible capital costs.…”

“…can be classified as a redundantly actuated, 3°-of-freedom parallel cable driven robot (CDPR) [41] . Due to a frameless design, it is scalable and relatively low cost compared to large gantry machines making it an accessible solution for DRAM when coupled with the concept of FGF/FPF printing using recycled feedstock [35] . The Hangprinter consists of 4 local anchors (3 on the ground and 1 on ceiling), which control movement of the Hangprinter end effector in 4 local axes (A, B, C and D axis) shown in Fig.…”

“…The A, B, C axes allow the end effector to move in plane while the D axis moves the end vertically. Parallel wires prevent the end effector from rotating around its own axis while moving along a given G-code path [35] . Through the unique Hangprinter kinematics, inverse and forward transforms allow conversion from cartesian coordinates to local joint angles and vice versa respectively.…”

“…2 in cutting G-code trajectories into straight line segments along the XY plane. where , , are line segments for the corresponding anchors, ( ) are the coordinates of the end effector, and (AX,AY, BX,BY, CX,CY) are coordinates of the anchors A, B, and C, respectively [35] .

Fig.

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“…The hybrid Hangprinter shown in Fig. 3 developed in this project offers the following modifications and improvements to the hybrid Hangprinter V3 developed by Petsiuk et al [35] : 32bit, ARM based microcontroller (DUET3 MBHC). Integrated motor control of NEMA 23 motors by the DUET3 board reduces overall footprint and complexities in wiring to provide a more plug and play solution.…”