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Université de Lorraine: Direct Waste Printing with PLA Pellets Versus FDM 3D Printing

French researchers from Université de Lorraine assess 3D printing techniques and recycling feedstocks, detailing their study in the recently published ‘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.’

While FDM (FFF) 3D printing has become highly accessible and affordable to users around the world, in this study the researchers also focus on the use of fused granular fabrication (FGF). Exploring the potential for continued ‘greening of distributed recycling,’ the researchers assess both FDM and FGF techniques for the desktop, experimenting with the following recycling filaments:

  • Commercial filament
  • Pellets
  • Distributed filament
  • Distributed pellets
  • Waste

Global framework of the experimentation. FFF, fused filament fabrication; FGF, fused granular fabrication; PLA, polylactic acid. Color images are available online.

A large part of the assessment included comprehensive studying of the granules (granulometry) used due to concerns regarding quality of reproducibility in the samples. Cost was substantially reduced, with material costing less than 1 €/kg – in comparison with 20 €/kg for commercial recycled filament. Better affordability coupled with quality in performance offers obvious benefit to users, with the potential for promoting a circular economy and efficient recycling.

“Due to the introduction of the open-source self-replicating rapid prototyper (RepRap), the dominant technology of 3D printing is fused filament fabrication (FFF) using polylactic acid (PLA),” stated the researchers. “Various forms of filament extrusion systems have proven effective at recycling PLA. However, PLA degrades with each cycle through the print/grind/extrude to filament/print loop.”

“This issue can be partially controlled by adding virgin PLA to recycled PLA, coatings, or carbon fiber reinforcement.”

By effectively eliminating the need to use filament and move directly to recycling waste, the researchers expect numerous benefits to continue emerging: reduced use of energy, faster production time, and less resources expending in making filament.

The following types of PLA were used:

  • Virgin, commercial PLA 4043D from NatureWorks (pellet form)
  • Recycled PLA filament from Formfutura for FFF printing
  • Recycled PLA filament produced in situ in ‘fablab conditions,’ meant for FFF printing
  • Pelletized feedstock for FGF
  • Shredded PLA from 3D printed waste, for FGF

In experimenting with the FFF system, the researchers used a Prusa i3 running Marlin firmware v1.1.9.

The FGF printer comprised a pellet extruder kit39 adapted to a commercial FFF printer (Créality CR-10S pro48) machine using a Marlin firmware v1.1.19. The pellet extrusion kit uses an auger screw with a diameter, cartridge heater –, and nozzle diameter that mixes and extrudes the melted material. The hot end of the FFF printer was adapted by replacing the pellet extruder prototype as shown in Figure 2. After the mechanical assembly was made, the first experimental tests were carried out to adapt the machine to the new parts and calibrate the formation of an extruded filament by using virgin PLA pellets. The extrusion factor was changed to calibrate the rotation of the screw extruder.

The FGF printer consisted of a pellet extruder attached to a Créality CR-10S pro 3D printer using Marlin firmware v1.1.19.

(a) FFF and (b) FGF printers used in the experimentation. Color images are available online.

Eight test samples were weighed and measured, and then evaluated for the following:

  • Tensile strength
  • Strain
  • Elastic modulus

Printability of shredded PLA materials. Color images are available online.

Printability of shredded PLA materials. Color images are available online.

“Regarding the economic aspect, using the FGF printer with virgin PLA pellets, there is a 65% reduction in printing cost per kilogram and a shorter production time compared with recycled commercial filaments, which is a non-negligible option. The results show that the main cost in 3D FFF printing is in the acquisition of filaments. However, the acquisition of recycled material filaments reduces the cost in relation to the acquisition of virgin material filaments, providing a reduction in the use of virgin raw material in 3D printing,” concluded the researchers.

“Opportunities arise in the possibility of using other types of recycled waste, including flexible and composite (plastic/plastic) materials as has been done on larger systems. Also, main factors such as polymer viscosity, which need to be controlled in the FGF process, are needed.”

Undoubtedly recycling will continue to be an ongoing theme in the 3D printing industry, with previous studies reflecting the state of recycling, solvent recycling, and circular chemical recycling. What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘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’]

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Pellet 3D Printing to Be Advanced by DSM and Juggerbot 3D

Dutch chemical company Royal DSM has announced a partnership with Youngstown, Ohio’s Juggerbot 3D to develop 3D printers and materials for pellet-based manufacturing. This represents greater momentum toward the adoption of pellet-based additive manufacturing (AM), which is sometimes considered to be the future of material extrusion 3D printing technologies. 

While DSM is already well-known within AM for its production of various materials for 3D printing, Juggerbot 3D is not yet quite a household name. The startup emerged from the Youngstown Business Incubator, with support from America Makes, as a manufacturer of large-scale, industrial-quality material extrusion 3D printers. While its initial filament-based systems are capable of high-temperature printing with high-performance plastics, Juggerbot more recently developed a form of fused granulate fabrication (FGF) for its P3-44 3D printer.

The machine has a build volume of 915 mm x 1,220 mm x 1,220 mm (36 in x 48 in x 48 in) and can manufacture parts at a rate of 4.5-9.1 kg/hr (10-20 lbs/hr). It features two interchangeable extruders, small and large for precise or fast printing, as well as mobile drying units for removing moisture from pellets prior to printing and an environmentally controlled build chamber. 

The Tradesman Series P3-44 pellet extrusion 3D printer from Juggerbot. Image courtesy of Juggerbot 3D.

The ability to 3D print using granules opens up a number of benefits. Not only can they be fed via hopper into the extruder more quickly than filament, but, because the materials typically used are readily available injection molding pellets, machine operators have a much wider portfolio of plastics to choose from. Combined with a high-speed deposition head and a large build chamber, pellet-based systems have the ability to 3D print large objects very quickly. Moreover, they are much, much cheaper than filaments.

After working together on filaments for Juggerbot systems, DSM and Juggerbot will now collaborate on the development of pellet-based industrial systems and materials. The Ohio startup’s existing FGF printer has been designed to print with DSM’s glass-reinforced PET polymer, Arnite AM8527, and DSM will be adding more pellet products to its 3D printing materials portfolio. 

DSM’s glass-reinforced Arnite AM8527 PET 3D printing material. Image courtesy of Royal DSM.

Support from the massive Dutch multinational, which rakes in about €10 billion in net sales annually, is obviously an important boost for the startup. For DSM, it’s not just a way to expand its sales, but to secure a position in the large-format and pellet extrusion markets. 

After all, BASF invested heavily in Essentium, which has developed its own form of large-format printing with technology meant to address the issue of Z-axis weakness. The chemical giant also recently partnered with Cincinnati Inc., which is known for its massive pellet extrusion machines (though the partnership is limited to its desktop filament printer for now). DuPont, too, sees pellet 3D printing as the future of the market, with Marketing Manager for Industrial & Consumer Christophe Paulo saying that “the bulk of the Material Extrusion market will be in pellet to parts.”

Pellet-based 3D printing technology is still early in its development as a market, with a comparatively small number of hardware manufacturers offering pellet machines. These companies typically come from industrial manufacturing backgrounds. Cincinnati, Ingersoll and Thermwood are all machine tool makers and Arburg is an injection molding company. It would make sense that these are the types of firms already sensing the way that the wind is blowing and one wonders if filament extrusion system manufacturers will catch on sooner rather than later. 

The post Pellet 3D Printing to Be Advanced by DSM and Juggerbot 3D appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.

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Green Fab Lab: Using the Fab Lab To 3D Print New Things From Recycled Plastics

Fab labs, growing in popularity around the globe, have a reputation for being smaller forums where the tools are provided for creative manufacturing, often centered around 3D design and 3D printing in a group setting. Materials obviously play a large role in these progressive environments. Now, researchers are studying a new program, outlining their findings in ‘Green Fab Lab Applications of Large-Area Waste Polymer-based Additive Manufacturing.’

A vast majority of 3D printing projects are created with plastics, causing the authors to explore the idea of fused particle fabrication/ fused granular fabrication (FPF/FGF) printing in a streamlined recycling manner—fabricating directly from a supply of plastic waste (FPF is one of the names for Material Extrusion 3D printing using granules or pellets). This concept would allow green fab labs to function as creative communities—but also as recycling centers. Open source industrial 3D printers would be necessary for such an operation, and the researchers chose the Gigabot X for this study, mainly, although an FFF 3D printer, the Lulzbot Taz, was used for fabricating more detailed parts due to its 0.5 mm nozzle.

Such an operation will embody the concepts of the following:

  • Open source symbiotic economies
  • Biomimicry
  • Regenerative design
  • Circular economy patterns

The Gigabot X 3D printer

Currently, numerous fab labs are exploring how 3D printing can be beneficial to the environment, beginning with the simple fact that it is ‘less environmentally detrimental’ than traditional manufacturing. Upcycling waste into filament is also becoming more popular, with numerous different types of machines being developed to handle this type of production for creating re-usable materials. the researchers point out that they have been responsible for successful recycling with a variety of different plastics, including PLA and ABS, and some other alternative materials too.

Sports equipment was printed for the project, and included a skateboard, kayak paddles, and snow shoes to complete the case study. Blender and FreeCAD were used for designing the products so that the open-source community would have access.

Printing times were as follows:

  • Skateboard – 11 hours, 54 minutes
  • Kayak paddles – 7 hours, 45 minutes (per set)
  • Snow shoes – 18 hours and 16 minutes (per set)

Overall, the researchers found that the Gigabot X offers definite ‘economical potential’ as a recycling system, and it successfully produced the ‘high-value’ sports products in all three case studies. The project was a success economically, even regarding use of electricity, and efforts spent customizing some of the parts substantially.

“For some products the profit potential and return on investment was substantial (e.g. over 1000%) for high capacity use of a Gigabot X. These results clearly show that the economic benefit of distributed recycling and on demand production of large, functional objects using an integrated FPF/FGF tool to promote circular manufacturing,” concluded the researchers.

Although plastics have many uses throughout the world, the question of what to do with them when they are no longer useful to us has become a topic of great concern, along with continued emphasis on recycling and the best methods for doing so—along with constant campaigning everywhere to encourage consumers not to dump items into landfills when materials can be re-used. Almost as soon as 3D printing blasted its way into the mainstream, what to do with all that plastic became an accompanying conversation, whether discussing cannabis containers being made into prostheses, following recycling 3D printing enthusiasts traveling the oceanside in mini-vans, or exploring the possibilities of recycling e-waste into 3D printers.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

Skateboard CAD file prepared for print

Finished skateboard

Kayak paddle CAD file prepared for print

(a) Finished kayak paddles (kid’s version) and (b) Finished kayak paddles (Adult version)

Snowshoe CAD file prepared for print

Finished snowshoes

[Source / Images: ‘Green Fab Lab Applications of Large-Area Waste Polymer-based Additive Manufacturing.’]