[backlog] March 31, 2020

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 21:520 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! ]

Like many of you, I've spent the last 2 weeks doing my very best to stay as far away from all of you as possible. While I've been trying keep my urge to be maximally productive during a global pandemic in check, the extra time at home has given me the opportunity to make some exciting progress that I'm excited to share with you!

I work at a local TrueValue hardware store, and due to the pandemic we've been out of N95 masks for weeks now. As an exercise in distributed design, I decided to see if I could print a mask from trash! I modified this design slightly so that it would print well with the trash printers large nozzle, and was able to print a remarkably comfortable mask frame in about 5 minutes!

Not an earth-shattering innovation, but a promising proof-of-concept for how trash printers could be used to create useful objects directly from locally available trash! The large nozzle of the Trash Printer allows it to crank out a mask in about 5 minutes, much faster than a typical 3D print, making it comparable in production time to injection molding, without the need for an expensive mold. The plastic I used for these masks came from Polypropylene test tubes, and the heat required to melt the plastic is well above sterilization temperature (260C/500F).

I was able to print and assemble 6 masks in an hour, most of which I gave away to my co-workers at the hardware store. Which is pretty neat! But the ability to do this in my basement isn't really particularly world-changing. My vision for the Trash Printer has always been to make it something that other people can ACTUALLY REPLICATE. I want to see this technology actually being implemented by other people, and so far the barriers to replication have been a bit too high. I'm working hard to fix that.

I got the original prototype of the Trash Printer working almost exactly one year ago! A major barrier has been that the gantry I'm using isn't my own design, isn't fully open source, and isn't specifically designed for trash printing. The MPCNC I've been using also requires nearly 60 hours of printing time, and so I've been trying to design my own version of a gantry, so that I can release the full plans for the WHOLE PRINTER, and not just the extruder, which I think will make the whole build a lot less daunting. For the past few months I've been refining a new design for the trash printer that uses laser-cut parts instead of 3D printed parts, which can be made much more rapidly, with a much wider range of materials, on a much wider range of tools.

All of this time "social distancing" has allowed me to refine this concept to the point where it's finally ready for real-world testing. While the design isn't particularly pretty, its extremely versatile, allows the use of lead screws or belts as the drive mechanism, and uses low-cost and widely available parts and materials. 

All of the parts can be laser cut out of just 3 sheets of 12x24" 1/4" plywood, or any comparable sheet material, using a laser cutter, CNC router, or they can be printed with a desktop 3D printer. The shapes are simple enough that one day I hope to be able to cut or print them using this gantry itself, so that once built a trash printer could trash-print more trash-printer parts.

That dream is still a ways off, but it's also closer than it's ever been! This month, I've spent your money buying the final parts and materials I need to dive into real-world prototyping of this new Trash Printer during April, to see what works and what needs more work. Once complete, this new design should be easy to fabricate, have a build area of 2.5x2x2 feet, be fully open source, and cost between $500-800 [Update 10/22: It's more like $1000-1500] to build.

Thank you, as always for supporting this work so that I can keep making my designs fully open-source, and stay tuned for the full design files for the first prototype of the Trash Printer V3!