Filament Roller Bearing

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. 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 smaller diameter down to 52mm
• V4 (OpenSCAD), highly customizable, with larger one-sided flange

After printing, please prep the roller according to the Post Printing instructions below.

All but one of my filament spools are accommodated by the 55mm version. I use this one when possible since the internals have better clearances than the 52mm version, allowing it to spin somewhat better.

V4 increases the size of the flange so the filament roll is less likely to walk off, with the realization that a flange is needed only on one side. Note that if the flange diameter exceeds the spool ID, it's necessary to remove the roller along with the spool.

Instructions for OpenSCAD:

• Open the .scad file in OpenSCAD version 2021.01 or later
• Press F5 to view the model
• Make sure Windows -> Hide Customizer is not checked
• Review/modify the Parameters in the Customizer
• Press F6 to render to STL, then press F7 to save the STL.

One of the customizer parameters is a checkbox to show a cross-section view (see image above). There is also a checkbox to test-print the bottom bearing only.