this is interesting. other than this machine, has anyone tried to make your own filament using raw pellets? https://www.kickstarter.com/projects/omnidynamics/strooder-first-truly-consumer-3d-printing-filament
I’ve made 120lbs or so on a Filastruder.
Disclaimer: Created the Filastruder. 
I’ve made my own with the Lyman extruder plans… Refining it for in house production of carbomorph 
Disclaimer: I own printrbot
Filastruder is a proven design