Filament spool roller

prusaprinters

***Works on the Creality Ender 3 Pro and Elegoo Neptune 4 Plus and most likely many other brands of printers that have a similar sized stock spool holders.***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 spin but only while extruding material.With the spool position on the left side of the printer, the bearing roller is positioned at about 10 o'clock. This allows the spool to rest against the original spool holder at about the 2 o'clock position which eliminates a free running spool and the rocking motion of the spool during retractions. A 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 spool rests back against the side 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.Print the _hex models to use M3x5mm or #4-40 x 3/16" machine screws and nuts.Or you can print the _insert models and use M3x4mm(OD)x3mm(Length) threaded brass inserts.Additional parts needed as mentioned above are:Two (2) M3x5mm bolts (or #4-40 x 3/16")Two (2) nuts (or M3x4mmx3mm threaded inserts)Two (2) 625 bearingsUpdate 01/10/2024: I originally designed this for my Creality Ender 3 Pro. I just got an Elegoo Neptune 4 Plus and found that my design fits it perfectly as well.  The Neptune 4 has a direct drive extruder so spool rocking isn't much of an issue during retractions BUT because the printer moves so fast, lighter spools will bounce around on the printer's spool holder. I'm unsure if this will affect print quality but the drag of the spool resting solely on the static spool holder could still be an issue for filaments like TPU.  Installing my spool roller on the Neptune silenced the spool from rattling and bouncing around and makes the filament feed out much smoother too. :)Updated 05/26/2021: I built two new models that have a curb or 'guard' to prevent the spool from rolling off the original spool roller (see the picture with the gray Duramic roll of filament). Note, only spools with a 55mm or larger hole will fit over these. These new models are only available with the hex nut option.  Note: I picked up a combo pack of Geeetech silk filament and the spools have a 52mm hole. They won't slide on over the “guard” model but since the spool cannot fall off the left side because the spool holder is fastened to the machine on that side, the fix was to print the Left bearing holder without the guard.  When I need to use a spool with the smaller hole, I can just remove the spool holder from the machine, load the spool and then reattach very quickly.  Updated 02/24/2021: Two new models included and tightened tolerance of bearing axles._Hex models use nuts_Insert model uses threaded brass insertsPrint SettingsRafts:NoSupports:NoResolution:0.2Infill:30%Filament: Paramount 3D (volcano),Duramic PLA+ (gray), Duramic PETG (red)Notes:I sliced this with PrusaSlicer using 2 perimeters, 5 top and 3 bottom layers and a 0.4 nozzle. I used a rear seam position and oriented the parts so the seam was near the gap where the bolt goes through and NOT on the thin area that wraps around the original spool holder. The roller is printed with the same settings. I used Duramic PLA+ gray for it and printed it standing up. The lower portion of the roller needed supports enabled for the bearing cup.Category: 3D Printer Accessories