Recycling Plastic With Liquid Nitrogen

Ln2

Recycling 3D printer filament isn’t a new idea, and in fact there are quite a few devices out there that will take chunks ABS, PLA, or just about any other thermoplastic and turn them into printer filament. The problem comes when someone mentions recycling plastic parts and turning them into filament ready to be used again. Plastics can only be recycled so many times, and there’s also the problem of grinding up your octopodes and companion cubes into something a filament extruder will accept.

The solution, it appears, is to freeze the plastic parts to be recycled before grinding them up. Chopping up plastic parts at room temperature imparts a lot of energy into the plastic before breaking. Freezing the parts to below their brittle transition temperature means the resulting chips will have clean cuts, something much more amenable to the mechanics of filament extruders.

The setup for this experiment consisted of cooling PLA plastic with liquid nitrogen and putting the frozen parts in a cheap, As Seen On TV blender. The resulting chips were smaller than the plastic pellets found in injection molding manufacturing plants, but will feed into the extruder well enough.

Liquid nitrogen might be overkill in this case; the goal is to cool the plastic down below its brittle transition temperature, which for most plastics is about -40° (420° R). Dry ice will do the job just as well, and is also available at most Walmarts.



		

The LATHON Dual Nozzle 3D Printer

lathon

Our friends at Freeside Atlanta have been keeping busy despite the city-stopping snowstorms they’ve been suffering recently. This time it’s a 3D printer with dual extrusion: the LATHON printer. [Nohtal] bought his first 3D printer only two years ago, but his experiences led him to build his own to overcome some of the issues he encountered with standard printers.

The LATHON keeps the bed stable and instead moves only the nozzles, using Bowden extrusion to reduce the weight on the moving parts. A key feature is the addition of a second nozzle, which usually limits the print area. The LATHON, however, maintains a 12″x9″x8″ build volume thanks to the Bowden extruders. [Nohtal] documents the majority of his build process on Freeside’s blog, including using a plastic from GE called Ultem 2300 for the print bed, and running the printer through its paces with a slew of materials: ABS, PLA, HIPS, Nylon, TPE, Wood, and Carbon Fiber. You can find more information on the Kickstarter page or at lathon.net

Check out some videos below!

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The FilaWinder

filawinder

The latest addition to the line of 3D printer accessories is the FilaWinder, a tool for winding your filament neatly onto a spool. If you’ve abandoned buying your filament by the reel in favor of making your own from cheaper pellets—such as the Lyman Extruder, the Filabot Wee, or other alternatives, including the winder’s companion product, the FilaStruder—then you’ve likely had to roll everything up by hand, perhaps after it flopped around on the floor first.

The FilaWinder spools for you while the filament extrudes, using a sensor to adjust the winding the speed to match extrusion rates as well as running it through some PTFE tube to gently coil it as it moves along. Perhaps most important, the FilaWinder provides a guide arm to direct the filament back and forth across the reel as it spools up, to keep it evenly distributed. Swing by their Thingaverse page for a list of printable pieces and their assembly guide can be found here, as well as on YouTube. You can see an overview video of the FilaWinder winding away after the break.

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Low Cost Filament Extruder

extruder

Here’s a great low cost filament extruder solution. It uses basic parts available from any hardware store, and a few 3D printed ones — estimated cost is well under $100.

It’s very similar to the Lyman Filament Extruder, but can be built for even less money. By using 200C set-point heaters, his setup requires absolutely no electronics — although a cheap PID controller from China could give him more extrusion capabilities with temperature control… Regardless, the system appears to make good filament and he uses it exclusively for his personal filament consumption in his Delta printer. He’s even hacked up the ABS casing of a refrigerator, ground it down, and turned it into filament using this machine! If you’re hungry for more details, the full build log and discussion can be found on the RepRap forums.

He also has a guide on making your own ABS color masterbatch to make your own filament colors!

[Thanks Liam!]

3D Printering: Alternative Filaments

printering

ABS and PLA are the backbones of the 3D printing world. They’re both easy to obtain and are good enough for most applications. They are not, however, the be-all, end-all filaments for all your 3D printing needs. Depending on your design, you may need something that is much tougher, much more flexible, or simply has a different appearance or texture. Here are a few alternative plastics for your RepRap, Makerbot, or other 3D printer:

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3d printer filament made of wood

Believe it or not, you can now squeeze wood through the nozzle of your 3D printer.

This new addition to the maker’s palette of 3D printer filaments comes from the mind of [Kai Parthy]. The new filament – going by the name Laywood – is a mix of recycled wood fibers and polymer binders that can be melted and extruded just like any other 3D printer filament.

Parts printed with Laywood have about the same properties as parts printed with PLA filament. One interesting feature of this material is the ability to add ‘tree rings,’ or a subtle gradation in color from a rich brown to a very nice beige. The color can be changed on the fly by setting the temperature of your printer’s hot end to 180° C for a light color, and 230° C for a darker color.

Judging from the ‘in action’ video of Laywood filament being pushed through a printer, the new wood-based filament works just the same as any other PLA or ABS plastic.

Outside eBay, there appears to be only one place to buy this filament. It’s not cheap at about €16/$20 USD per half kilogram, but hopefully that price will come down when it becomes more popular.

Video after the break.

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Win $40,000 for squirting plastic out of a nozzle

3D printers such as the RepRap and Makerbot turn spools of plastic filament into just about any object imaginable. There’s a problem though: this filament costs about $40 a kilogram, and raw plastic pellets cost about 1/10th of that. Obviously, there’s a lot of room for improvement. The folks at Inventables are throwing $40,000 at the problem in a contest to build a machine that takes plastic pellets and turns it into usable plastic filament.

The object is simple: build a device that takes ABS or PLA pellets and turns them into a 1.75mm filament. The machine has to cost less than $250, be able to add colorant to the plastic, and be usable in a 3D printer. The winner gets $40,000, a laser cutter, a 3D printer, and a CNC milling machine courtesy of Inventables. Sign up on the official contest website and don’t be shy about sending your progress into the Hackaday tip line

If you’d like to get started, here’s a great page that goes over the basics of plastic extrusion, and a few attempts (1, 2) from [Adrian Bowyer] and [Forrest Higgs] that show exactly how hard this is. There’s also the Filabot that had a successful Kickstarter, but there’s apparently been no (or very limited) progress in the four months since the Kickstarter. I’ve even given this idea a go, but am currently stuck at manufacturing a proper auger. To put this in perspective, this is the moonshot of the current crop of 3D printers; a simple device to lower the barrier of entry to 3D printing is desperately needed, and we’ve got to give props to the Inventables crew for putting this contest together.