Search Terms
Plastic pelletizer
Plastic granulator
Fiber Chopping Machines
Industrial plastic filament chopper
Filament Granulation
Polymer Granulation
Granulation effects on polymer
mixing polymer granules or pellets
Articles and Papers about Filament Choppers or Pelletizers
High Speed Pelletizer, no size control: https://www.thingiverse.com/thing:397524
Low speed cutter, using same hardware as the Recyclebot extruder: http://www.soliforum.com/topic/5159/filament-pelletizer/
Industrial Fiber Choppers: https://www.chopcot.com/fiber-chopping-machines/index.html
Peer reviewed
Granulated Plastic in concrete (Composite): https://www.sciencedirect.com/science/article/pii/S0956053X07003054
I couldn't find any peer reviewed articles about the process of turning filament into pellets, all I could find was companies that use the technology to make their base resins or composite masterbatches.