Filament spool roller for Ender by Hemi345

Last crawled date: 3 years, 3 months ago

Updated 12/16/2020 with shorter spool roller for the Ender 3 Pro.
During repetitive retractions and deretractions, a full/heavy spool can start rocking back and forth causing strain on the extruder gear and lead to filament grinding and/or artifacts in the print. I've tried a few different filament holder designs with ball bearings and either had the spool unwind while printing causing tangles or they needed table space to set the spool on. I came up with this design that utilizes the stock spool holder to keep everything attached to the printer while allowing the spool to easily roll only while extruding material.
With the spool position on the side of the printer, my bearing roller is positioned at about 9 o'clock. This allows the spool to rest on the original spool holder at 12 o'clock while being supported on the side which eliminates a free running spool and the rocking motion of the spool during retractions. I gentle pull on the filament from the extruder transfers some of the weight of the spool onto the bearing roller allowing it to smoothly feed out filament until extrusion stops at which point the weight of the spool rests back on the top of the original spool holder. This setup has worked great for printing PLA, PETG and especially TPU where the filament feed needs to be as smooth as possible to prevent stretching.
I designed this around small 625 ball bearings so spools with a small inner hole diameter of 52mm can still fit. 625 bearing specs are 5mm ID, 16mm OD, 5mm width and can be easily bought on Ebay, Amazon, etc.
To clamp these to the original spool holder securely, I used M3x5mm hex cap head bolts with M3x4mm(OD)x3mm(Length) brass threaded inserts. Use a soldering iron to push the threaded insert in from side with the bearing.
Included in the STLs is left and right brackets and roller.
Additional parts need as mentioned above are:
Two (2) M3x5mm bolts
Two (2) M3x4mmx3mm threaded inserts
Two (2) 625 bearings