The Trash Printer - Version 3

An open-source, low-cost, large-format 3D printer that can print directly from shredded plastic trash instead of filament

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The Trash Printer is an open design for a large-format 3D printer that can print new and useful objects directly out of shredded plastic trash. It has been tested to work with shredded Polypropylene (#5) and Polyethylene (#2 and #4) which together make up over 50% of all household plastic waste. It uses a 1/4" (4.5mm) nozzle, which makes it VERY tolerant of dirt, labels, and adhesives, which are common in post-consumer waste streams.

The parts it makes are incredibly strong, light, and flexible, more comparable in terms of strength to parts made by traditional injection molding processes than those made by most desktop 3D printers. The better you clean your material, the better your prints will look, but if you're lazy like me, you can just throw your trash in without even cleaning it first. Skipping the filament-making step entirely reduces the recycling process to just two steps: Shred, and Print.

This project is a totally redesigned new version of the Trash Printer, which I originally built as part of my entry to the 2018 Hackaday Prize. This new design includes the original extruder head, but now also includes full documentation for the entire 3D printer gantry as well. 

This new design is cheaper, easier to build, and makes bigger parts than my previous two versions, and is fully open-source!

To give you context for what a breakthrough this new design is for me, it helps to understand how I got to this point. So gather around kids, and let me tell you the story of the Trash Printer.

It all started way back in 2016, when I first built the Precious Plastic open-source plastic shredder, using money from my Patreon. The shredder allowed me to shred up plastic trash into small flakes, and it's what got me started on this whole wild project.

In March of 2017, I built the Precious Plastic Extruder, and I was finally able to start extruding those shredded plastic flakes into... well, basically spaghetti. The Precious Plastic community has done some truly incredible things with this extruder, but making anything useful with it is time consuming and requires a lot of skill, and to be honest, I didn't really have the patience for it.

But the long strands of plastic that came out of the extruder looked a lot like 3D printer filament, and it got me thinking. The day I built the extruder, I took it over to the CNC router in my friends' shop, and  I said, "I wonder if we could just strap this to a robot...?"

In December of 2017, I started making design sketches, taking what I had learned from the Precious Plastic design, and putting it on a vertical axis so that it could act as a 3D print head.

In February 2018, I started asking my friends who knew about 3D printers how I might go about getting the extruder actually moving. At the time, I knew basically nothing about how 3D printers worked. With A LOT of help (Big thanks to Darcy N, Molly M, Jonathan D, and Nathaniel G) I 3D printed the parts to build the MPCNC (Mostly Printable CNC) designed by V1engineering. I picked that gantry because it was cheap, 3D-printable, and it used common, hardware store parts.

My goal was to figure out how to build a fully functional Trash Printer by October of 2018, as just one part of my submission to the 2018 Hackaday Prize. It proved to be a lot more difficult to do than I had hoped, and by the time the deadline for the Hackaday Prize arrived, I had only succeeded in building the gantry and getting the printer moving for the first time, making these first, very basic shapes.

The deadline came and went, and I failed to make it to the finals, and I gave up on it for a while. I wasn't able to even look at it again for a few months, but in the spring of 2019, I finally made my first actual prints, with actual layers, which were the first things you could really call "things".

After that, my prints improved quite quickly, but I was still limited to pretty basic shapes, and the prints weren't very consistent. I started using shredded up polypropylene test tubes as my feedstock, which provided a nice, stable, clean material to test with, even though it wasn't really the same as using post-consumer household trash, which was always my goal.

One of the first things I ever printed was this little, 4" tall "wind turbine". It was a promising proof-of-concept, but hardly functional. Still, it did prove to me that the concept was workable, and until that point, I hadn't really been sure if what I was trying to do was even possible.

By the Summer of 2019, I was printing simple vases pretty consistently, but not with real trash, and not anything very big. I kept messing around with settings, and testing out new motors, upgrading from a NEMA23 stepper motor to a NEMA23 with a 5:1 planetary reduction (I'm now using a 15:1 reduction), in order to get more torque.

I decided that I needed a bigger...

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Trash Printer

This ZIP folder contains: - All the design files for the Trash Printer (.SKP) - All the build files for the Trash Printer (.SVG and .STL) - All the build files for the Precious Plastic Shredder V2.1 (.STEP and .DXF) -All the config files for the firmware, control software, and slicer.

x-zip-compressed - 41.95 MB - 06/11/2022 at 21:05


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  • 1
    Replicate the Information

    I am fascinated by the idea of disruptively useful information. 

    Disruptively useful information is information for how to do or make something so incredibly useful that it challenges the status quo. In order to be disruptive, disruptively useful information cannot be simply a neat idea or a promising technology, it must be the specific practical application of a useful idea. In order to be useful, disruptively useful information must be both both useful and accessible. People must be able to understand how to do it and why to do it, so well that they actually do. In order to be information, disruptively useful information must be a discrete unit of information, a complete set of plans, that contains ALL of the information required for the idea to be replicated anywhere by anyone.

    I do not believe that the Trash Printer is disruptively useful information, not yet anyway. Disruptively Useful Information is simply the name of the game I'm playing, not a high score that I'm claiming to have achieved. You can play the "Disruptively Useful Information" game too, and together, maybe we can score some points. Keeping score in the "Disruptively Useful Information" game is very simple: "How many times has it been replicated?"

    The Precious Plastic shredder is one of the best examples of disruptively useful information that I can think of. If you aren't already aware, the Precious Plastic community is a movement of people from all over the world, who share plans for small scale plastic recycling machines with each other, so they can all turn the trash around them into new and useful stuff. 

    It's an incredibly inspiring project, and I highly recommend that you look into it more if you're intrigued.

    The coolest thing about the Precious Plastic machines, IMHO, is that the plans are freely available for you to download, and if you have access to them and the means to follow them, you and your friends can build your own plastic recycling workshop. Disruptively Useful Information spreads like a meme. 

    If you see it, and you like it, you can copy it, and you can change it. You can do whatever works for you without asking for permission, and if you figure something out that works particularly well for you, you can share that with others. That kind of rapid, global, decentralized hacking is what gives me hope that we may actually be able to find ways to adapt to the challenges that we face, as quickly as we need to, come what may.

    Current High Scores:

    The Precious Plastic Shredder.... 1,000+ Known Replications

    The Trash Printer V2 ........................1 Known Replication

    The Trash Printer V3........................0 Known Replications

    License: All that is to say, I have waived my rights to the documentation contained in Trash Printer V3 release with a CC0 Public Domain License. 

    Do with it what you will. Drive it like you stole it. You are not legally required to attribute me or share-a-like, but I humbly request that you do.

    If you do replicate your own version the Trash Printer, please let me know by commenting on this page or on my Patreon.  I would love to see photos of the stuff you build with it.

    If you think that it sucks and there's something I should change, I probably agree that it sucks and that should be changed, so I invite you to fix it and let me know how it goes!  If you make improvements, please post your changes in the Github Repo.

    If you appreciate the work I've put into this project, consider becoming a Patron! Everything I make is posted publicly for everyone to see, but patrons give me a working budget to keep hacking, and get access to a private Discord server.

  • 2
    Build your Community

    The Trash Printer itself will probably cost somewhere between $400-800 to build, depending on what tools, skills, and parts you have access to. 

    The Precious Plastic Shredder can cost anywhere from $600 if you have a lot of tools and are super handy to $2500+ if you just want to buy one from someone else. The shredder is not required, but without a shredder of some kind you will not be able to print with your trash.

    A 2kWh solar generator and a 300-400 watt solar panel will cost another $1500-3000, and should be able to generate roughly 1-2kWh of electricity over the course of a day, in most climates, most of the year. The Trash Printer V3 has a recycling efficiency of roughly 1 watt-hour per gram, or one kilowatt hour per kilogram, including shredding, so a solar powered Trash Printer should be able to process 1 kg of plastic waste per day.

    Personally, I've found that I generate roughly a kilogram of Polypropylene (#5) trash per month. That number may fluctuate wildly from person to person, but assuming 1 kg shredded plastic/per person/mo, one Trash Printer *should* be able to meet the polypropylene waste needs of roughly 30 people, using nothing but sunshine as its energy source, and nothing but trash as it's material source.

    All that is to say, like the other Precious Plastic machines, the Trash Printer can be an expensive and difficult tool for one person to build, but a very affordable and easy tool for a small community of people to build. So if you want to build one, try asking for help! Talk about it with your friends and comrades. Pitch it to your school, business, city, or maker space. See who has the skills, space, spare parts, tools, and time or money you need to make it happen.

  • 3
    Acquire the Tools

    To assemble the Trash Printer, you will just need a few basic tools:

    A power drill

    A router or jigsaw

    2 x Adjustable wrenches or Ratchets with bits for 5/16-18 and 1/4-20 nuts and bolts.

    M3, M4, M6 hex keys.

    A razor blade

    To fabricate the parts using the build files, you will need access to either a laser cutter or CNC router capable of cutting 1/4" material, or a 3D printer. 

    Yes, you can print some of the parts for a Trash Printer with a Trash Printer, and no, you can't print all of them with a Trash Printer. Cutting the parts will make it go a lot faster, the parts were designed to be cut in 2D in order to make them easy to make on the widest range of machines possible. You may need to make modifications to the designs to suit your needs.

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