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Cake day: June 18th, 2023

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  • It’s nice to see more projects in this area, but there have been many others. Heck, the venerable Filastruder launched its Kickstarter in 2013. The Lyman / Mulier extruder design is still available on Thingiverse (for free).

    Considering that the ExtrudeX kit doesn’t include hardware, only STL files and a list of needed parts, the price point is hardly compelling. Selling commercial licenses for what effectively amounts to nothing but the plastic body is a bad joke. Also, it’s hard to tell from the provided pictures, but it looks like this design lacks any filtration for the melted plastic (the extruder is a rotating metal screw inside a metal tube - there will be shaved off metal bits coming off of it into the melted plastic that you really don’t want going into your filament).

    In any case, extruding filament from finely shredded bits isn’t the difficult or expensive part of recycling 3D print waste at home. Shredding it in the first place is. Breaking down plastic objects into small pieces is really very difficult and requires an almost cartoonish amount of torque, which is why all of the machines available for doing this are expensive. Also, if you want to get decent quality output you have to be careful about how you process the material (sort it, shred it, clean it, dry it). Any mixed plastic types (e.g. that one PETG benchy you printed awhile back and forgot that you threw in with your other PLA waste) or foreign material (bits of metal from the shredder, random hairs because you’re not working in a clean room, that one part that you forgot you glued together, a threaded insert you forgot to take out, etc) is going to jam up and possibly damage your equipment.

    The ExtrudeX project only gives a brief nod to this in the FAQ:

    Do I need a shredder or special grinder for the waste?

    You do not need a big industrial shredder. You only need to break your waste into small pieces that can fit into the hopper and move through the screw. This can be done with simple tools or a basic home grinder, as long as the pieces are not too large.

    Right… you “only need to break your waste into small pieces” that can fit down what appears to be a 1cm tube. Best of luck doing that by hand.

    If you want a realistic idea of how difficult the whole process really is, watch Stefan’s (CNC Kitchen) videos that I’ve linked above and/or watch Jonathan’s (The Next Layer) attempt to build a 3D print recycling system (he’s sunk 21 months and thousands of dollars into it).