3D printing can produce quite a bit of waste over the years that usually lands in the trash. Wouldn’’t it be great. If you could recycle your failed prints, support structures and purge blocks into new filament. Today, I’’ll show you how I managed to extrude new filament out of scraps at home. Guten Tag everybody! I’m Stefan. And welcome to CNC Kitchen Recycling failed prints is something like the Holy Grail of 3D printing. There have been DIY filament extruders around for a couple of years that enable you make your own material out of resin pellets that you can purchase. They are basically built up pretty simple. A high torque low rpm motor drives an auger. So big wood drill that sits inside of a pipe. The pellets are then added via a slot into that pipe and get transported to the front where very similar to a 3D printer, a heating element and a nozzle sits. The melted plastic then flows out of the nozzle and “tada”. There is your filament. On these simple extruder’s, the diameter of the filament is only partly defined by the nozzle and is also dependent on temperature flow rate weight of the filament that stretches the just extruded portion and a couple more. This was maybe a bit exaggerated. Since most systems can be quite sensitive to small changes, but making your own filament at home is totally doable, even though maybe not reasonable in monetary terms. If are okay with some tinkering. Though there is not a lot of information about people who recycled 3D printing scraps and made new filament out of it. I bought myself a Filastruder Kit a couple of months ago and finally got around putting it together. Honestly, the built itself Wasn’’t the most straight forward thing, and also the first couple of runs Weren’t always a success and I had to use the file on some of pieces and straighten the pipe so that everything ran smoothly. I also purchased the so called. “filawinder”, which is a separate unit that directly winds the filament rolls and is essential. If you want to extrude PLA with a consistent diameter. Both Filastruder and Filawinder kits will set you back around $500 but the design is quite simple, and there are also a couple of open source designs around that you can mostly build from hardware store parts. At first, I ran almost a pound of the included ABS to clean out the extrusion part before I went to my desired. Material: PLA! After setting up everything properly and tuning everything in getting filament with a kind of constant diameter, didn’’t seem to be a huge problem. The thing that was bothering me, though, Was that if you don’’t want to buy? PLA pallets in bulk quantities. A kilo of PLA pallets cost me almost 10€ which comes quite close to a cheep roll of generic filament. So if you want to save money on filament with such a system, you’’ll have to print quite a bit. Now we get to the interesting part. And this is recycling old PLA prints. I have been gathering all of my PLA scraps for the last year and paid a lot of attention that I don’’t mix any other material in there, which would then spoil my material properties. The thing is that I can’’t just put these parts into the extruder to get filament because the material that is fed can’’t be larger than 5 mm, on any side. In order to shred the material, I tried to applied two techniques. The first one was to use a modified paper Shredder that can cope with lots of parts if they are not too thick. I made myself a plunger that I don’’t accidentally get my fingers into the dangerous shredding bits. Bigger parts need to be broken down at first. At the moment, I’’m doing that by hand. But maybe a wood chipper would help me there. Michael, over at Teaching Tech has also done some investigation on that topic. So check him out. The particles that come out of the Shredder Often Don’’t meet the 5MM requirement. So I additionally run everything through this cheep mixer? If you have a proper one to spare than you could maybe do most of the shredding directly in it. Only make sure that you don’’t run if for too long and melt the plastic inside. You should also really wear a couple of safety. Google’s since shredding can produce quite dangerous plastic shrapnel? The material is now run through a sieve that I 3D printed by using no top and bottom layers and only adjusting the infill density to a point that the mesh size was around 5 mm. Everything that’’s too. Big goes back into the mixer. The remaining particles are now basically usable. The only thing that just needs to be done is to properly dry them because otherwise we’’ll get extrusion issues. I simply put the shreddings into a laundry bag and put everything in my food dehydrator that I also use to dry my filaments at 65°C for a night. Normal PLA pellets are usually extruded at around 160°C in the Filastruder, which gives you a slightly undersized filament with the standard nozzle and works perfectly in basically any 3D printer. If you increase the flow multiplier a little. Running my first tests. I noticed that if I run the recycled filament at these low temperatures, some particles don’’t perfectly melt and give the material a grainy texture. After bumping the temperature up all the way to 175°C the material extrudes very smoothly, but due to the lower viscosity of the melt ends up way undersized, so I drilled the nozzle to 21mm Anyways. So the shredded and dried PLA scraps are now added to the hopper. After a bit, the filament starts to extrude it is slowly guided through the position sensor to the winder. Even though the line laser might look like a laser measuring device, it’s actually only used to sense how far the extruded filament has sagged and then winds it up a bit so that the tension on the filament caused by its own weight stays more or less constant. Extruding the recycled plastic actually worked. Well, the only real problem. I had was that the sharp cornered Shredding’s tended to jam in the hopper, so I had to constantly gently hit the it to get a uniform material output. I tried adding a fan with half of the fins removed, but that didn’’t really help either. In a second run, I added 50% Virgin PLA pallets to my recycled material, which then fed really well and created a quite consistent and beautiful filament. The 100% recycled material that I kind of Fed manually ended up with an average diameter of around 1.60mm and varied in the range of +-50um. The extrusion rate is around 100g an hour, So a full roll will take quite a while. The color, of course, is a mixture of all of the parts you recycled. I call my first batch “trash Bag Khaki”. The material has a nice, smooth surface and feels like regular PLA and isn’’t overly brittle. Even though I mixed my shredded plastic. Well, the color is not perfectly constant over the roll, and I think it’’s kind of impossible with such a setup. That doesn’’t really bother me, though, and I’’m thinking about getting some black pigments in order to overtone the rest of the colors and get a nice black filament in the end. All of the parts I printed so far came out very nicely. I didn’’t have any jams So far, maybe also because I use a melt filter, which is a fine mesh in front of the nozzle that keeps bigger particles from getting into the filament. And this might be one problem of recycled filament. Not only do you really need to pay attention that you only shred the same type of plastic. You also need to be aware that any dirt on your recycled parts will end up in your filament. So I might be trying to wash my particles before drying to get even better results in the end. This was my prove of concept on recycling scrap 3D prints into new, very usable filament. I didn’’t go into huge details on the setup and everything since I really want to hear what you guys wanna see. The things I think I still need to tackle is how I can properly shred all of my old scraps and how I can feed them consistently in the hopper. I still think I was very successful, and even though this might not be something for everyone. I really want to do more in this direction. So I’’d really like to hear your ideas on this topic. Where could I improve? What other investigations should I do? Do you think recycling scraps is worth the effort? Please let me know down in the comments. Thanks for watching everybody. 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