Sherpa Mini - Tailed filament cutter

Since I was struggling getting reliably good filament tips with some filament, I decided to make my own design. First I tried The Printing Shark's design, but I did not like how the spring worked, or how the blade was mounted.

The general concept stayed the same, a simple arm mounted #11 blade, moved by the toolhead itself, bumping on a fix mounted block somewhere on the printer frame. However I decided to use a 3mm steel pin as an axis of rotation, and 3x M2x6 screws to mount the blade on the arm. I changed the spring for some 6x3mm magnets - the one in the arm and the base should repel each other, to return the arm as far as it can push. Then a second magnet on the small “tail” of the arm pulls the arm to a stable resting position. This way it will not rattle under normal printing (at least at 10k accel, more my machine is not capable reliably), and will have enough movement range to perform reliably the cut movement, and upon release to return back to the resting position. The blade was hidden from below as much as it could be done, and it was also sunk in the arm itself, to decrease the risk of cut fingers as much as possible. 

The filament path has generous chamfer and radii to aid the movement of the filament to the hot end. 

The mounting pattern is designed to work on a Sherpa Mini extruder as a middle piece between the hot end and the extruder itself. My intention was to design this module, to integrate it into my very space restricted toolhead, which is for now working as intended - in 100 filament changes did not have a single misfeed, stuck filament, or partial cut. As I get more hours and filament changes into the toolhead, I will share also its design.

BOM: 

1x #11 Exacto blade - the tip should be broken off by pliers

1x 3mm pin, length around 15mm

3x 6x3mm magnet

3x M2x6 screws

Print settings: 

Rotate parts on the flattest side to achieve best print quality. I printed mine on the back side (with the smaller opening) with a small tree support for the overhang in the middle

Due to larger heat expected above heated bed and hot end, at least ABS or ASA is recommended to use - PETG or PLA may creep over time and in theory can release the blade

Layer height of the arm 0.1mm, to allow for the very thin blade to be seated in the arm

I used 4 walls, 6 bottom and 8 top layers, infill 20%, however the design is forgiving in terms of print settings

Big thanks to Sakitume for testing an earlier version of this cutter!

Retained the general idea of a blade mounted on a rotating arm. However my design is made from ground up, to be able to design a more reliable mechanism, using common magnets and a steel pin as the rotation axis