The LYMAN FILAMENT EXTRUDER V3 is a complete filament extruding assembly for extruding 3D printer filament. It extrudes and winds the filament onto a spool which it then ready for use.
The BOM shows a cost figure of near $900. The extruder alone can be made for under $250.
See the video on YouTube:
This Thing has been a 6 month project. The uploaded manual will give you the information on making your own. I have included a cad dfx file for those who wish to improve, correct, add to or make for resale. As there are many folks with more know how than me, any suggestion with documentation is welcomed. Good luck, WORLD.