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An overview of the proposed manufacturing process for recycled polymers, comprising 1) Granulation , 2) filament extrusion and spooling, 3) FDM 3D printing and 4) Printed final structures.
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p>In this study we aim to investigate recycling of waste plastics products into filaments for use in a typical FDM 3D printing system. We investigate the parameters relating to control of the filament thickness to a variety of different plastic types, which include HDPE and ABS. Following filament generation, parameters were investigated to optimis...
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... this approach granule sizes of be- tween 3-7mm in diameter and 2-3mm in thickness could be repeatable produced. Figure 1 shows a picture of the resulting polymer granulated products used in this study. Typ- ically in a commercial filament generation system, pelletised product would be used. ...
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Citations
... Perhaps even better than shipping 3-D printing feedstock to an area needing humanitarian aid would be using local materials and then only needing to ship the equipment, which includes 3-D printers and recyclebots (waste plastic extruders that make filament for fused filament-based 3-D printers) (Baechler et al. 2013;Zhong et al. 2017;Woern et al. 2018a, b;Mohammed et al. 2018a;2022). This approach has been proved successful with a range of common plastics including acrylonitrile butadiene styrene (ABS) (Mohammed et al. 2017;Zhong and Pearce 2018), high density polyethylene (HDPE) (Baechler, et al. 2013;Chong et al. 2017;Mohammed et al. 2017;2019), linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) (Hart et al. 2018), polypropylene (Pepi et al. 2018;Zander et al. 2019), and PET (Lee et al. 2013). In addition, there are open-source printers that can directly 3-D print ground plastic waste from a wide range of materials using fused particle fabrication/fused granular fabrication (FPF/FGF) at both the small-scale (Volpato et al. 2015;Whyman et al. 2018;Alexandre et al. 2020) and the large-scale Cartesian based systems (Woern et al. 2018b;Byard et al. 2019;Reich et al. 2019;Little et al. 2020) and hangprinter/cable robot (Petsuik et al. 2022). ...
... Perhaps even better than shipping 3-D printing feedstock to an area needing humanitarian aid would be using local materials and then only needing to ship the equipment, which includes 3-D printers and recyclebots (waste plastic extruders that make filament for fused filament-based 3-D printers) (Baechler et al. 2013;Zhong et al. 2017;Woern et al. 2018a, b;Mohammed et al. 2018a;2022). This approach has been proved successful with a range of common plastics including acrylonitrile butadiene styrene (ABS) (Mohammed et al. 2017;Zhong and Pearce 2018), high density polyethylene (HDPE) (Baechler, et al. 2013;Chong et al. 2017;Mohammed et al. 2017;2019), linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) (Hart et al. 2018), polypropylene (Pepi et al. 2018;Zander et al. 2019), and PET (Lee et al. 2013). In addition, there are open-source printers that can directly 3-D print ground plastic waste from a wide range of materials using fused particle fabrication/fused granular fabrication (FPF/FGF) at both the small-scale (Volpato et al. 2015;Whyman et al. 2018;Alexandre et al. 2020) and the large-scale Cartesian based systems (Woern et al. 2018b;Byard et al. 2019;Reich et al. 2019;Little et al. 2020) and hangprinter/cable robot (Petsuik et al. 2022). ...
The purpose of this life cycle assessment study was to determine the life cycle impacts for production and distribution of a humanitarian supply item under various supply chain paradigms in order to illustrate the potential environmental benefits of organizing production and supply operations for these items in novel ways. To do this, a case study is used on a family-size water storage and dispensing bucket, such as the 14 L capacity polyethylene bucket commonly produced by Oxfam International. The LCA is a cradle to gate including production and transportation of PE plastic feedstock, fabrication of the water bucket, and transportation of the bucket to a common distribution site representative of a humanitarian aid location. Three different humanitarian aid locations are used to illustrate the range of potential impacts for each processing and supply system: Nepal, South Sudan, and Peru. Six processing and supply scenarios were investigated: (1) centralized Oxfam traditional system, (2) centralized commercial Chinese supply and distribution, (3) quasi-centralized Field Ready supply and distribution, (4) distributed supply and distribution system with 3-D printing, (5) distributed supply and distribution system with 3-D printing and local waste feedstock, and (6) distributed supply and distribution system with extrusion molding and local waste feedstock. The results found the major contribution to total GHG emissions are electricity usage for manufacturing and shipping feedstock and final product. Among Systems 1–3, System 1 and System 2 are environmentally poor as the electricity emissions in Pakistan and China are high. System 3 was an improvement as the products are manufactured locally. Decentralized supply and distribution system with 3-D printing (System 4) is less compatible with regions of high grid emissions. In System 5, the same equipment has been used, but with local waste feedstock, which shows an improvement of 67.7% for Nepal and 65.5% for Peru because of the reduced shipping emissions, even if the manufacturing emission is the highest among all of the systems. System 6 is feasible for all three locations. It is concluded that manufacturing should be prioritized on grids where the electricity emission is lower using local waste feedstock as it is the most efficient approach; however, a further study should be done on operating the FPF/FGF 3-D printer or extrusion molding systems powered with distributed photovoltaic systems in order to complement this process and produce the most environmentally responsible production.
Graphical Abstract
... For example, Bergaliyeva et al. [63] and Kumar et al. [64] compared the properties of recycled Polylactic Acid (PLA) and virgin PLA 3D printing filaments to establish the feasibility of 3D printing as a method for recycling plastics. Mohammed et al. [65] compared the properties of recycled ABS and HDPE as standalone polymers and fused in a ratio of 90% ABS and 10% HDPE. The comparisons proved reliable in demonstrating the comparative strength of virgin and recycled polymer filaments for 3D printing. ...
... The resulting filaments also have a high glass transition temperature, suggesting they are suitable for high-temperature applications. Likewise, Chu et al. [66] also found that mixing polypropylene and polystyrene wastes by Fuse Filament Fabrication yields 3D printing filaments with 32 MPa more mechanical strength in comparison to their respective virgin materials at extrusion temperatures of about 230 • C. Mohammed et al. [65] also established that a combination of 90% ABS and 10% HDPE produces filaments with consistent 3D prints and mechanical strengths up to 20% higher than the parent virgin material for the respective polymers. The findings consistently demonstrate that combining recycled polymers can produce 3D printing filaments with exemplary mechanical properties. ...
... Likewise, Chu et al. [66] also found that mixing polypropylene and polystyrene wastes by Fuse Filament Fabrication yields 3D printing filaments with 32 MPa more mechanical strength in comparison to their respective virgin materials at extrusion temperatures of about 230 °C. Mohammed et al. [65] also established that a combination of 90% ABS and 10% HDPE produces filaments with consistent 3D prints and mechanical strengths up to 20% higher than the parent virgin material for the respective polymers. The findings consistently demonstrate that combining recycled polymers can produce 3D printing filaments with exemplary mechanical properties. ...
The increased use of plastics in industrial and agricultural applications has led to high levels of pollution worldwide and is a significant challenge. To address this plastic pollution, conventional methods such as landfills and incineration are used, leading to further challenges such as the generation of greenhouse gas emissions. Therefore, increasing interest has been directed to identifying alternative methods to dispose of plastic waste from agriculture. The novelty of the current research arose from the lack of critical reviews on how 3-Dimensional (3D) printing was adopted for recycling plastics, its application in the production of agricultural plastics, and its specific benefits, disadvantages, and limitations in recycling plastics. The review paper offers novel insights regarding the application of 3D printing methods including Fused Particle Fabrication (FPF), Hot Melt Extrusion (HME), and Fused Deposition Modelling (FDM) to make filaments from plastics. However, the methods were adopted in local recycling setups where only small quantities of the raw materials were considered. Data was collected using a systematic review involving 39 studies. Findings showed that the application of the 3D printing methods led to the generation of agricultural plastics such as Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), Polyethylene Terephthalate (PET), and High-Density Polyethylene (HDPE), which were found to have properties comparable to those of virgin plastic, suggesting the viability of 3D printing in managing plastic pollution. However, limitations were also associated with the 3D printing methods; 3D-printed plastics deteriorated rapidly under Ultraviolet (UV) light and are non-biodegradable, posing further risks of plastic pollution. However, UV stabilization helps reduce plastic deterioration, thus increasing longevity and reducing disposal. Future directions emphasize identifying methods to reduce the deterioration of 3D-printed agricultural plastics and increasing their longevity in addition to UV stability.
... According to studies in the literature, it has been determined that cumulative energy is reduced by 41-64% in the production of polymer-based materials produced with 3D printers (Kreiger and Pearce 2013). Besides, NFRPCs produced with 3D printers are known to reduce carbon dioxide emissions and carbon footprint compared Cellulose with traditional production techniques (Mohammed et al. 2017;Victoria Santos et al. 2022). In 3D printing, i.e., additive manufacturing (AM), the designed parts are produced in layers, rather than subtracting from a larger part. ...
The study investigated the properties of alkali-treated hemp fiber-reinforced polycarbonate (PC) composites that can be formed by 3D printers for architectural applications. To determine the optimum alkali treatment to be applied to the fibers, the properties of the samples treated with 5% and 7% sodium hydroxide (NaOH) at both ambient temperature (AT) and 120 °C (HT) were determined by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). It was determined that the alkali treatment that gave the optimum result was 5% HT. Composite specimens with fiber/matrix ratios of 10/90, 20/80, and 30/70 were prepared in filament form to be printed in a 3D printer as alkali-treated and untreated. These composites were characterized by conducting tensile strength, FTIR, differential scanning calorimetry (DSC), TGA, and scanning electron microscopy (SEM) analyses. Tensile strength results revealed the highest mechanical performance for 5% NaOH alkali-treated and 10 wt.% hemp fiber-reinforced PC composites. DSC results showed that slight changes occurred in the glass transition temperature values. Furthermore, SEM analysis showed that 5% NaOH-treated hemp fibers have better interfacial bonding with the PC matrix than untreated fibers. As a result, more natural and sustainable materials have been obtained for architectural applications without significantly decreasing in PC properties.
... 7 Efforts are being made to identify sustainable feedstocks for 3D printing. 23,24 Several studies have expanded the range of recycled filament materials including PLA, 25,26 ABS, 27,28 PET, 29,30 HDPE, 9,27,31 and PC. 32 In fact, Ref. 18 describes a comparative life cycle assessment in a low-density population case study in Michigan (USA) and estimated that a distributed approach could save approximately 100 billion MJ of energy per year from the recycling of 984 million pounds of HDPE. ...
... 7 Efforts are being made to identify sustainable feedstocks for 3D printing. 23,24 Several studies have expanded the range of recycled filament materials including PLA, 25,26 ABS, 27,28 PET, 29,30 HDPE, 9,27,31 and PC. 32 In fact, Ref. 18 describes a comparative life cycle assessment in a low-density population case study in Michigan (USA) and estimated that a distributed approach could save approximately 100 billion MJ of energy per year from the recycling of 984 million pounds of HDPE. ...
The high volume of plastic waste and the extremely low recycling rate have created a serious challenge worldwide. Local distributed recycling and additive manufacturing (DRAM) offers a solution by economically incentivizing local recycling. One DRAM technology capable of processing large quantities of plastic waste is fused granular fabrication, where solid shredded plastic waste can be reused directly as 3D printing feedstock. This study presents an experimental assessment of multi‐material recycling printability using two of the most common thermoplastics in the beverage industry, polyethylene terephthalate (PET) and high‐density polyethylene (HDPE), and the feasibility of mixing PET and HDPE to be used as a feedstock material for large‐scale 3‐D printing. After the material collection, shredding, and cleaning, the characterization and optimization of parameters for 3D printing were performed. Results showed the feasibility of printing a large object from rPET/rHDPE flakes, reducing production costs by up to 88%.
Highlights
Study: multi‐material recycling printability of PET‐HDPE.
Large‐scale fused particle‐based 3‐D printing technically possible.
Direct waste 3‐D printing rPET/rHDPE flakes, reducing production costs up to 88%.
... The study concluded that distributed recycling of HDPE for 3D printing filament is an environmentally sustainable alternative to traditional virgin filament production. Mohammed et al. [174] conducted an LCA to evaluate the environmental impact of reusing plastic waste for 3D printing filament production. They compared two different types of plastic waste, HDPE and PLA, to virgin materials. ...
... The majority of FDM 3D printers today primarily use thermoplastic-based filaments as feedstock materials. These filaments are characterized by diameters ranging from 1.75 to 3.0 mm, depending on the specifications of the FDM 3D printer (Pan et al. 2016;Mohammed et al. 2017). The key benefits of FDM 3D printing include cost efficiency due to short lead times, the ability to fabricate complex parts, minimal waste generation, and energy efficiency. ...
This study deals with the development of 3D printable bionanocomposites using poly(lactic acid) (PLA) with ≤ 2% D-lactic acid content and cellulose nanofibrils (CNFs). The CNFs were extracted from the waste sawdust of Eucalyptus grandis via chemical and mechanical techniques. Thermogravimetric analysis (TGA) revealed that the CNFs were thermally stable within the intended processing temperature ranges. In this study, a combination of solvent casting and melt extrusion techniques was adopted in the production of PLA containing 1 wt% and 3 wt% CNFs. The neat PLA filament was brittle and frequently broke during fused deposition modelling (FDM) 3D printing. However, the incorporation of triacetin as a green plasticizer resulted in improved filament flexibility and eliminated the inherent brittleness. TGA analysis revealed a slight reduction in the degradation temperature of the bionanocomposites when compared to neat polymer; however, all the specimens were thermally stable within the processing temperature. The scanning electron microscopy images of the 3D printed specimens revealed the presence of voids across the fracture surfaces. The tensile analysis of 3D printed specimens revealed that the PLA/CNF bionanocomposites exhibited higher tensile modulus, and elongation (strain) when compared to PLA-based specimens. The tensile strength of the 3D-printed 1 wt% bionanocomposite specimen was 12% higher than that of the neat specimen, whereas the 3 wt% bionanocomposite remained comparable to neat PLA. In summary, the morphological, tensile and 3D printing analysis revealed that the bionanocomposite filaments possessed adequate roundness, flexibility, and strength. The as-prepared filaments performed well under low printing temperatures without warping.
... Polymer granules or Pellets ( Byard et al., 2019;Zhou et al., 2022) Collected waste plastic is processed as polymer pellets by chemical or mechanical recycling to use as raw materials and decrease the demand for virgin plastics. Composite products (Babafemi et al., 2018;Mohan et al., 2021;Mtibe et al., 2023) Recycled plastic is mixed with wood fiber, concrete, or others to form composite materials and used as pipes, furniture, packaging, etc. 3D Filament (Gaikwad et al., 2018;Mikula et al., 2021;Mohammed et al., 2017) Waste plastic is reprocessed as a 3D printer filament for various industrial applications. Pavement application (Kalantar et al., 2012;Vasudevan et al., 2012;Zhao et al., 2020) Waste plastic is blended with bitumen to create a durable asphalt pavement that enhances service life and reduces the consumption of virgin materials. ...
... This way, the bottle roller can be held in place and the connectors and reinforcement bars can be eliminated and ensure overall strength and stability. In addition, to reduce the purchased components the PVC pipes can be replaced by 3-D printed pipes or extrusion molded pipes from an open source recyclebot [62][63][64][65][66]. Moreover, the bottle roller is customizable to be used in different scale applications. ...
Proprietary bottle rolling systems automate some laboratory applications, however, their high costs limit accessibility. This study provides designs of an open source bottle roller that is compatible with distributed digital manufacturing using 3-D printed parts and readily-available commercial components. The experimental results show that the open source bottle roller can be fabricated for CAD$210 (about USD$150) in materials, which is 86% less expensive than the most affordable proprietary bottle roller on the market. The design, however, is more robust with enhanced capabilities. The design can be adapted to the user’s needs, but is already compatible with incubators with a low profile (dimensions 50 cm x46 cm x8.8 cm) and capable of being operated at elevated temperatures. The systems can be adjusted to revolves from 1 to 200 RPM, exceeding the rotational speed of most commercial systems. The open source bottle roller as tested has a capacity greater than 1.2 kg and can roll twelve 100 mL bottles simultaneously. Validation testing showed that it can operate for days at 80 RPM without human intervention or monitoring for days at both room temperature and elevated temperatures (50 °C). Future work includes adapting the designs for different sizes and for different fabrication techniques to further reduce costs and increase flexibility.
... This way, the bottle roller can be held in place and the connectors and reinforcement bars can be eliminated and ensure overall strength and stability. In addition, to reduce the purchased components the PVC pipes can be replaced by 3-D printed pipes or extrusion molded pipes from an open source recyclebot [62][63][64][65][66]. Moreover, the bottle roller is customizable to be used in different scale applications. ...
... On the other hand, landfilling of plastic wastes occupy a lot of space and requires a long time to decompose because they are not often non-biodegradable. As a result, the linear economy paradigm (based on the "take-make-dispose of" model) has devastating effects on the environment, including depletion of natural resources, environmental pollution, and non-sustainable development [5,6,10,12,14,18,[20][21][22][23]. ...
... Different scholars investigate the possibility of utilizing recycled waste plastics as source material for 3d printing filament. For example, HDPE and ABS plastic wastes [21], PET bottles [9,14,32], polypropylene [5], PLA [23], and ABS [33] has been examined for 3D printing filaments material. ...
... Mohammed et al. [21] examined the recycling of HDPE and ABS plastic wastes into FDM 3D printing filaments to refine print parameters and create a range of demonstration models. The results show that the proposed supply chain can produce highly repeatable ABS and HDPE filaments with diameters of 1.74 ± 0.1 mm for ABS and 1.65 ± 0.1 mm for HDPE materials. ...
Plastics have become the most popular and ubiquitous material in our daily lives and global plastic production has increased significantly. A large portion of the plastic is used to produce disposable packaging items, which are discarded and accumulated as post-consumer wastes both on the land and oceans. Distributive recycling of waste plastics through additive manufacturing became the most effective solution to overcome environmental pollution and reduce the use of fossil oils and gases. With the rise of additive manufacturing, the demand for polymers has increased exponentially and many scholars are concerned about how 3D printing filaments should be reproduced from recycled plastics. This review aimed to study the potentials of using recycled plastic for 3D printing filament to minimize environmental pollution and preserve material sustainability. The study revealed promising results for the use of recycled post-consumer plastic as a more sustainable and environmentally friendly 3D printing filament material. The impact of plastic degradation on their mechanical and thermal properties due to subsequent extrusion and contamination of plastics by impurities was also studied. Besides, the additive materials used to enhance mechanical properties and increase the molecular weight of recycled material are discussed. Finally, a conclusion is drawn and future research opportunities are also addressed.
