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[backlog] October 31, 2021

A project log for 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

sam-smithSam Smith 10/07/2022 at 23:020 Comments

[ Backlog - This log was adapted from my Patreon, to fill in the details about how this project has developed over the years. Check the link for the full post, and if you appreciate this project, consider supporting it! ]

3 years ago, I entered this wacky project into the Hackaday Prize, which challenged makers to "build the best hardware module or device possible for the boldest solution you can envision." I pitched the idea of a trash-powered plastic recycling system, which was the boldest solution I could consider a the time. It still is, though my understanding of the problem has evolved considerably since then.

The idea was selected as a first-round finalist in the 2018 Hackaday Prize, but you had to demonstrate a working concept of your proposed idea to make it to the finals, and by October of 2018, I was no where close. 

I had learned enough about woodgas to get an engine running on it, and I had built most of the V1 Trash Printer, but had never really printed anything useful. I had proven to myself that the concept could work, but actually making it work was still well beyond me.

I fell far short of my goal to demonstrate a working prototype, where biomass energy was used to power a shredder to shred up plastic to print in to useful plastic objects. But, with your support, I kept at at, in this month I finally achieved a major milestone!

For the first time, I was able to operate the Metabolizer system using entirely off-grid power, using solar power to generate woodgas from amazon packaging and woodchips, and used that gas to power the generator, which powered my Precious Plastic shredder as I shredded up take out containers, and then fed them to the Trash Printer, which printed a small sign and a cup over the course of roughly 4.5 hours, using only trash and sunshine as fuel, a new record!

It's the first time I've operated whole system under its own power in real time. There are still a lot of improvements that I  need to make before it reaches it's next milestone, which is sustain operation for a full 24-hour period. To do that, I know that I'll need more solar panels, and a bigger battery bank. But now I have a benchmark to work from, and set of parameters to minimize and maximize.

So I spent this month's budget on a new livestreaming camera and a big SD memory card, so that I can record and livestream these runs in realtime, powering the camera from the system, so that when the power dies, the stream dies. My goal is to be able to broadcast my runs to Twitch, keeping a record of each try and recording it's results each time. 

The video above was my first attempt at doing that, so I recorded the whole thing, but didn't go live. The camera did great, though, and now I have a play-by-play recording of what happened that I can learn from for the next run.

Now that I've got the Trash Printer printing again, I've been printing all sorts of new stuff. I printed this neat skull vase to fill with candy for Halloween. That streak of black/gray you see near the bottom is what happens when I mix in charcoal dust from the biochar reactor into the hopper of the Trash Printer, sequestering a tiny amount of carbon, and making the plastic more UV resistant!

The biochar mixed with shredded Polypropylene test tubes gives the plastic a really nice "smoky quartz" effect!

Thank you so much for your support all these years!

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