Hello all! For 3 years now I’ve been working towards building a 3D printer that prints directly from flakes produced by the Precious Plastic shredder, without the need for making filament first. This spring, I was finally able to print actual objects, and just yesterday I finished and published my documentation for Version 3.1.0 (Versioning convention: Major redesigns . improvements to design . improvements to documentation)
Polypropylene and HDPE both have relatively high thermal warp characteristics, which make them more difficult to print with, especially for small, detailed parts, compared to PLA and ABS, which is why they aren’t more widely used in 3D printers. However, together PP and HDPE make up over 50% of all plastic waste by volume! Making actual post-consumer plastics into high quality filament that won’t clog a printer, in addition to PP and HDPE being hard to work with to begin with, led me to try and just scale down the basic Precious Plastic extruder design so that it would be about the same size and weight as a CNC router, so it could fit on an existing CNC router gantry and 3D print larger, lower resolution parts without the filament step, reducing cost and complexity.
So far, I’ve printed vases, bowls, cups, geodesic dome connector parts, and brackets for mounting solar panels to the roof of my bus. The printer only takes >200W peak/100W average, and the parts mentioned above took about 30-60 minutes each, so that works out to an energy cost of 50-100wH per part, or roughly the power it takes to fully charge a laptop. The parts are wonderfully light, strong, and flexible. They don’t have nearly the same resolution or detail as typical printed parts (the nozzle is currently 10x the size of a typical desktop printer nozzle) but they are also highly tolerant of impurities, such as food or label bits, and there is still a wide range of useful objects that can made at this resolution, and with a smaller nozzle and a higher-precision gantry, major improvements in resolution are probably possible. I’m particularly excited because there is a whole class of objects this printer can print that could previously only be made by high-pressure industrial injection molding, and can now be made as one-off custom parts a very small scale, at very low cost.
You should be able to mount this extruder to any existing CNC router that is powered by stepper motors, can support the weight of a router, and has at least a few inches of Z travel. I built mine around the mostly-open-source (open but non-commercial) Mostly-Printable CNC (MPCNC), which only cost about $500 to build.
Next steps for me are:
-Making a smaller, more detailed version for printing small detailed parts in PLA
-Making an 2’x8′ long gantry, for printing full honeycombed interlocking beams and trusses that are structurally comparable or superior to lumber and can be easily assembled into tiny homes and other deployable structures.
-Building more heads for different plastics- PLA, LDPE, PET (dried), and ABS.
Making this documentation took a lot of work, and made me appreciate just how much work Dave had to put into make the original set of tutorials and plans so that we could all actually replicate them. So please use it! Replicate! Replicate! Replicate!
I’m a Patron of Dave’s on Patreon, and have my own Patreon, which is Patreon.com/DisruptivelyUseful. If you appreciate this work and have the means to chip in some money, it will help me prototype and improve this system faster, but all of my documentation is freely available to everyone. You can also follow my progress on Instagram – @themagictoolbus