MK3/MK4 Filament Spool Holder

6/16/24 UPDATE: The filament wore a grove in the edge of the original Filament Guide so that the filament no longer slide side-to-side. A designed an updated Guide that has a Aluminum stand-off (Steel would be even better, but I already had the aluminum one!) fastened in place as a wear surface. But it does require some hardware. It can be found at:

https://www.printables.com/model/914382-filament-guide

4/11/24 UPDATE: I had trouble with the assembly coming loose on the printer crossbar when changing filament, so I added a clamp at the bottom of the assembly to hold it in place. I also opened up the slot for the crossbar so the assembly fits down fully on it. The clamp is held in place with two M3x10mm Machine screws and nuts. The nuts are printed in the Arms. Insert a material change at the following layers (based on 0.20mm layer height - I don't know why they are slightly different!)

• Left Arm: Layer 218
• Right Arm: Layer 219

The clamp also holds the two Arms together so they do not have to be glued. While adding the hardware violates my design goal #4 below, it seems like a good trade-off. Hopefully you can use a couple of spare screws and nuts from your original printer build.

________________________________________________________________________________________________________________

I designed this spool holder with the following advantages:

1. Doesn't sag to one side when holding a single spool. (I only print with one color at a time anyway).
2. Totally contains the spool so that the strong vibrations from the MK4 printing at high speeds won't disrupt it.
3. I wanted a detachable filament guide because I only use the guide for tall parts.
4. I didn't want to use any external hardware. The assembly needed to be 100% 3D printed.

This design satisfies all these requirements. The spool is held in place with a screw-in spindle which requires only one revolution to secure. The threads are oriented so the natural unwinding of the spool acts to keep it tightened. The filament guide can be added/removed with the filament loaded in the printhead (via. the diagonal slot in the top of the guide). The entire assembly wedges in place on the top frame element, so no tools are required to attach or remove it.

This assembly will accommodate spools up to 3" wide.

The Arms and the Spindle can be printed without supports. I used organic supports for the filament guide. I used a 5mm brim on all parts for extra stability. Also, I struggled to get the Arms to print using PETG. The hex pattern on the build plate acts like many little parts, which results in a lots of strings and globs. I switched to PLA and they printed fine.

The knurl on the spindle was created with a very cool OpenSCAD program “knurledFinishLib.scad” written by aubenc @ Thingiverse (http://www.thingiverse.com/thing:9095).

Please post your makes and likes if you like the design! Thanks!