Filament Roller

Filament Roller Bearing
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Here is a novel method for reducing the friction of rotation of the filament spool on 3D printers. It's essentially a wide linear bearing with an inner shell, outer shell separated by arrays of captive needle bearings on each end. The printed object is entirely print-in-place and no other parts are needed, apart from lubrication. On my Ender-3 this prints in ~8 hours with only ~50g PLA.

See my demonstration video in the link below.

Some benefits of reducing the friction are:
* less chance of delicate filaments snapping
* less wear on the filament ingress guide hole
* more force available to push filament
* less crimping of the filament by the gear teeth

I can hardly imagine using the printer without the roller anymore.

(Updated Jan 27, 2020 to add V4)

I've included the STL and source files for two versions of the roller:
* V2 (FreeCAD), suitable for filament spools with inner diameter minimum 55mm
* V3 (FreeCAD), handles spools with smal