Mechanical Properties and Applications of Recycled Polycarbonate Particle Material Extrusion-Based Additive Manufacturing

Abstract

Past work has shown that particle material extrusion (fused particle fabrication (FPF)/fused granular fabrication (FGF)) has the potential for increasing the use of recycled polymers in 3D printing. This study extends this potential to high-performance (high-mechanical-strength and heat-resistant) polymers using polycarbonate (PC). Recycled PC regrind of approximately 25 mm2 was 3D printed with an open-source Gigabot X and analyzed. A temperature and nozzle velocity matrix was used to find useful printing parameters, and a print test was used to maximize the output for a two-temperature stage extruder for PC. ASTM type 4 tensile test geometries as well as ASTM-approved compression tests were used to determine the mechanical properties of PC and were compared with filament printing and the bulk virgin material. The results showed the tensile strength of parts manufactured from the recycled PC particles (64.9 MPa) were comparable to that of the commercial filament printed on desktop (62.2 MPa) and large-format (66.3 MPa) 3D printers. Three case study applications were investigated: (i) using PC as a rapid molding technology for lower melting point thermoplastics, (ii) printed parts for high temperature applications, and (iii) printed parts for high-strength applications. The results show that recycled PC particle-based 3D printing can produce high-strength and heat-resistant products at low costs.

Open Source Waste Plastic Granulator

“…The particle sizes demonstrated in Figure 10 are small enough to use in a wide array of recyclebots (both commercial and homemade) as well as for direct printing via FPF/FGF as demonstrated in references [58][59][60].…”

“…The values are operated on by a linear calibration, and then written to a microSD card, with time stamps generated by the on-board real time clock. The size characteristics of the particles for the resultant granulated material were quantified using digital imaging and the open source Fiji/ImageJ using techniques discussed previously [60]. ImageJ works by analyzing a photograph of the particles and raising the contract of the photograph until all particles are clearly recognizable to the program as solid black pieces.…”

“…Figure 10 shows the resultant particles and particle size distribution, where it is clear that the majority of particles are fines with total areas under 10 mm 2 . These particle sizes are appropriate for the majority of recyclebots as well as direct material extruder-based 3D printers such as the Gigabot X [58][59][60]. Using the initial acoustic measurements, an expansion chamber was designed ( Figure 9) that could be attached to the five-gallon bucket shop vacuum, and a 3D model was produced to utilize PVC and a 3D printable components to reduce noise from the operation of the device.…”

“…These fused particle fabrication (FPF) or fused granular fabrication (FGF) 3D printers are becoming established in the academic [49][50][51][52][53][54], maker [55][56][57], and commercial venues (e.g., GigabotX, PartDaddy, Cheetah Pro, David, Erecto-Struder, etc.). FPF/FGF printing is possible with recycled materials [58][59][60], as is using FGF printing of molds for distributed injection molding of larger replicate products [60].…”

Desktop Fabrication of Strong Poly (Lactic Acid) Parts: FFF Process Parameters Tuning

“…Along with broad distribution and drastic price reduction of FFF machines and consumables, the Rapid Manufacturing is now more and more often replaced with Distributed Manufacturing term, implying the shift from making exclusive products to massive production of commodities [31][32][33][34][35][36][37]. Laying aside FGF machines, operating on polymer pellets or regrind, as described in [38,39], the following tendency can be formulated. While the performance of machines printing with molten polymers has only increased several times since their appearance, the average price of such a machine reduced by several orders of magnitude.…”