Magnetic Filament Filter (Updated Dec 2019)

thingiverse

### Updated December 2019 I needed several more of these for my Prusa MK3S MMU2 setup, so I redesigned this to make it easier to build, maintain, and reduce friction with filament. It should be more affected by gravity than filament moment, which is handy for the long retracts needed for the MMU. Update 2: v13 fixes a small stress joint issue from v12 with the fingers that hold the magnets, where a couple of these cracked or snapped off on the first five sets I made. Also, cleaned up the entry/exit holes. What you need: * Two each of printed parts: 2019_12_Filter_Cover.stl and 2019_12_Filter_Middle.stl * Eight 3x4mm cylindrical magnets, which are very common on eBay and AliExpress, 200 usually cost less than $8 shipped * A clean dust cloth; I used Swifter, but the 3M industrial stuff or anything similar should work as well * Scissors Assembly: The photo shows how to do this, but if you prefer words. Insert magnets into the bare middle frame. Put all magnets in the same polarity for one frame, then the opposite for the other. If you get it wrong, this version makes it easy to remove them and try again. Cut the dust cloth into 15x40mm strips and fold in half. If the material is thick, try 15x20mm without a fold. Place the dust cloth on the inside of the cover as illustrated, then snap a middle frame over it, making sure it's the correct way up. Repeat for a second half. If you got the magnets the right way around, two halves should hold together. ### Old Version I had printed one of the many other hinged filters here and after a few removals, the clip broke. A binder clip fixed that, but it was annoying. Made this quick little filament filter held together with magnets. Easy to take off and put on. No clips to break. Fusion 360 source file included. Been using this one for a couple months now, and it works quite well for cleaning the dust off filament. A bonus I've found from the design is that when not in use, the magnets allow it to be stored on the extruder stepper or the metal side of the printer. What you will need: * Two prints of each part * Eight 3mm diameter 4mm tall cylindrical magnets (can be acquired on eBay for a couple money units) * Two strips of your favorite flavor of dust cloth (I used Swifter) Assembly: Press the magnets into the holes. Make sure to have them the right way up with all north poles up one side and south up on the other. If you get it wrong, it will do the opposite of holding itself together. Bent the "spring" parts up slightly on either side of the ridges. Wrap a strip of dust cloth around the "spring". Fit the "spring" under the clips on either side of the holder. The dust cloths last a long time in this thing and can be rotated around the "spring" part when it's dirty.