This is a two spool filament roller with a two chamber buffer box underneath for a small footprint. I use a dry box with five filament rolls leading through PTFE up to a buffer box, then through the bottom of the workbench and up to the MMU2S. This means changing filament colors is a bit time consuming, so this Spare Filament Roller provides an easy way to add a color or a specific roll for a specific print.
All printed items (print two of the Diverters)
Two (2) PTFE tubes, 11” long
Two (2) PTFE tubes, long enough to get to your printer from the box
Four (4) PC4-M6 compression fittings
5mm (#9) drill bit
M6x1.0 tapping tool
PLA should work fine as well.
Most the parts are printed with these settings, and 3 perimeters all the way around.
The deviations are below:
The Diverters were printed at .3 Draft, with 20% infill and 2 perimeters all the way around.
The Top Plate was printed with 5 bottom layers and 4 top layers, printed flat on the bed, to give strength as it spans the open buffer box and holds the weight of the spools.
The Front Plate has two holes printed in it. They should be lightly reamed with a 5mm (#9) drill bit, then tapped with an M6x1.0 tap. Thread in the PC4-M6 compression fittings. Do not over tighten!
At the rear of the Main Body (the end with the sloped ramps) there are two indentions printed into the vertical wall above the ramps. You’ll need to drill them out with the same 5mm (#9) bit. The holes should angle downwards, at the same slope as the ramps, and just slightly inwards (towards the center of the project). See pics for orientation. Tap these hole with the M6x1.0 tap then thread in the PC4-M6. I found a small open ended wrench makes this easier as there’s limited room for fingers near the ramps. Do not over tighten!
Glue the Diverters into the Main Body. With the back (ramp end) of the Main Body oriented to your right, glue one Diverter, roughly centered, along the vertical wall nearest to you. The Diverter should be flush to the wall, and flush to the bottom bed of the Main Body’s buffer tray. I used CA glue (gel) with an activator pen for all glueing.
Next slide the Mid Plate into place along the tracks in the vertical side walls of the Main Body. The Plate may or may not require one or two spots of glue to stay in place, depending on print tolerances. It should fit tightly across the top of the lower Diverter you just installed.
Then glue in the top Diverter. It should sit against the opposite wall from the lower Diverter, roughly centered, and should sit flush against the vertical wall and flush against the Mid Plate.
Dry fit the 5/16” rods through the rod support towers on the Top Plate. The holes in the towers may need to be slightly reamed, or the rods polished smooth if they’re rough. The rods should not fit too tightly, as they’ll put undue pressure on the towers, which aren’t printed to be strong in that orientation. The rods should slip through the towers with only minor effort if properly fitted. Remove the rods and set them aside.
Assemble all the Bearing Case Halves onto the Bearings. I used the smallest spot of CA glue on each half to hold them together. While they press nicely into place, I’ve had them separate over time/use when not glued, so it’s easier to glue them together now. Use absolutely minimal glue here!
Once the eight bearings are assembled, assemble one Bearing Stop on one end of each rod. Gentle tapping with a mallet against a solid surface will help seat them flush to the end of the rod. Slide one Bearing down each rod to the Stop. Now slide each rod through the first of the rod support towers. Add two more bearings to each rod, then continue the rods through the second support towers. Now add the last Bearing to each rod, and finally cap the rods with a Bearing Stop. The Top Plate Roller Bearing assembly is complete.
This is your last chance to check the internal assemblies of the Main Body before sealing the buffer box. Double check that everything is solidly in place and as you want it!
Lastly, glue the Top Plate to the Main Body along the edges. Make sure there’s a spot of glue at each corner, and the small edges near the open end (just past the recesses for the Front Plate catches).
Install the 11” sections of PTFE to the rear compression fittings. Cross them and push the ends up through the two PTFE towers near the middle of the Top Plate. Crossing the tubes removes tight bends in the PTFE and eases the travel of the filament. Alternately, you could use longer pieces of tubing and create a gentle 360 degree loop in them before routing them up through the towers, without crossing them. This takes up more room behind the buffer box, but keeps the spools oriented correctly to the tubing.
Lastly, press the longer PTFE tubes into place on the compression fittings on the Front Plate.
Assembly is complete!
Designed entirely in Fusion 360...