Ample work has been done on filament extrusion. Because of the potential of recycling material and/or using pellet source material, and cost saving through that. (Printing_Material_Suppliers contains a list of sourcing for filaments.)
This page list methods of making filaments by method. There are at least two other pages. GranuleExtruder and Granule Extruder Team(mostly links). Probably there is a need to separate the abstract from particular incarnations of the idea.
Q: is it true, and to what limit, that larger filament diameters make the filament cheaper by weight?(possibly depending...)
Q: difference between PLA, ABS and other?
All methods i have seen feed pellet/ material into some kind of hot end where it melts. One potential problem of course is the heat creeping from the hot end and clogging everything when things cool down.
Auger vertically in the container with material
I suppose the advantage might be that gravity is less likely to deform things, making an slightly oval cross section. Cases are:
- GranuleExtruder, i think (as of 12-2012) those are by nophead.
Auger horizontally with hopper
AFAICS this idea seems to have been applied to actually make filament more.
- LYMAN FILAMENT EXTRUDER II with designs and BOM by hlyman. (Note variants exist and look for newest/good versions) Looks pretty complete.(check the pdf) From PDF, appears to be able to produce filament with +/-0.05 mm accuracy from fine granules. Pricepoint is >$250
- greenman100 made one that already ran some kgs. (about 1kg/day as i understand it)(apparently he is elmoret in http://soliforum.com/ .) It's now "Ready for Beta Testers!"
Basically a piston moves back and forth and pellets fall in.
plastic filament from recycled plastic
- "Perpetual plastics project and their Ultimaker": Perpetual Plastic Project somehow (details?) converted recycled plastic cups into filament, then used that filament to print stuff out on a Ultimaker.
plastics from starch
I hear that "Brandon121233" makes plastics from starch. "Make Potato Plastic!" and "Starch Plastic 2.0- Pressure Cooker Hacking". What modifications, if any, are required to use either plastic in a standard Mendel RepRap? Is there a page anywhere on the RepRap wiki that discusses how to make plastic out of stuff that can be grown locally? --DavidCary 16:42, 14 March 2013 (UTC)