Look into extruder setups. There have been countless kickstarters on that, google is your friend !
Oh look, the 1st result of a search ! http://www.instructables.com/id/Buil...actory-Filame/

And Oh, the third result : https://en.wikipedia.org/wiki/Lyman_filament_extruder

Seriously though, it is an auger screw with a hotend, all able to withstand 200°C. Not rocket science. Being able to extrude consistant diameters is something else though.