Filament Sharpener for Prusa MMU3

Got bored and annoyed at hand-trimming filament ends to feed cleanly through the MMU3 prior to tip forming during printing.  Normally this isn't something one would do often, but I've been doing a bunch of testing after a hotend rebuild and have needed to reshape filament ends more than I prefer.

Very simple pencil sharpener-style device.  Feed path sized and angled for consistent smooth feed through the MMU and stock extruder setup.  Uses fairly standard, commonly-available pencil sharpener blades, though the cheapest option I found at the time was this pack of generics I stripped the blades from:

https://www.amazon.com/Mr-Pencil-Sharpener-Handheld-Sharpner/dp/B08158738F

Single-sided, single-bevel blades are frustratingly difficult to source for a lot of things, so I defaulted to the lowest-hanging fruit.  I'll be banging together a chamfering tool similar to this one for accurately trimming the 'nose' of the hotend PTFE tube while keeping it centered and preventing wall collapse or snag.  Why yes, I did run out of spares...

Round shape is easy to twirl around the filament (hold that firmly with your other hand), and the rudimentary knurls give good traction on the body.  Print using lots of perimeters, to give the screw something to bite into when securing the blade.  One end of the blade path is pocketed for a secure hold, while the other is opened up a bit to give room for sliding the blade into place.  Fairly self-explanatory: the rounded/filleted end of the blade goes in the rounded notch, and screw goes into the hole directly under the blade.  Sharpening the filament goes quick, so you only need a couple turns to get the job done.

Enjoy.

(fixed part orientation - Fusion being a pain)