Filament Cutter for Neptune 3 Pro / Plus / Max

NOTE: Redesigned filament cutter for Neptune 3 Pro Plus Max coming soon, but this variant is easy to get into :) 

As I wanted to venture into building an AMS/MMU of my own, or prepare in anticipation of Klipper AMS systems like BIGTREETECH ViVid to come out, I wanted to see whether there is a way to have the Neptune 3 printers adapted to have a filament cutter without needing to perform tip tuning. After looking at a SEFC from DrawModelPrint, I came up with this. All done in Tinkercad, so I don't have step files. Should be compatible with most Klipper based AMS/MMU systems such as ERCF, TradRack, 3MS, HTLF, BoxTurtle, NightOwl, etc. 

BOM:

* Spares are nice to have in case things wear down

Requirements:

• Klipper firmware configured with AMS/MMU

Print Instructions:

• Print 1 of every item, except Filament_cutter.stl or Filament_cutter_stock_shroud.stl. Choose whether you are using stock shroud (or Hero Me shroud), or if you are using different cooling setup like WindWarden 5015 mounts
• 20% Gyroid infil 0.2mm layer height. PLA works with no problems
• Filament_cutter.stl or Filament_cutter_stock_shroud.stl need to be printed with M6 hole facing up (ie oriented the same way as it would be mounted, see pics). Use supports, Make sure to put support blockers everywhere in the path of the blade assembly.
• Enable bridging for Filament_cutter.stl or Filament_cutter_stock_shroud.stl 

Assembly Instructions:

• Screw on PC4-M6 to the top of Filament_cutter.stl or Filament_cutter_stock_shroud.stl
• Attach #4 blade to Filament_cutter_blade_holder.stl - the small inner bump should keep the blade secured, with some movement
• Insert the blade assembly into the rectangular hole opening - the blade assembly should move freely in and out
• Take 304 SS Torsion Spring, and cut one of the legs short enough to fit inside the cavity of Filament_cutter.stl or Filament_cutter_stock_shroud.stl, and then slide it into the top nub
• Press fit M2 nut into the hex opening under the spring
• Attach Filament_cutter_arm.stl to the Filament_cutter.stl or Filament_cutter_stock_shroud.stl by first lodging the longer leg of the spring into the opening on the arm, then positioning it under the spring. Use M2 screw from the top to screw the two together. 
• Attach the Filament_cutter_arm.stl mid portion with the blade assembly with M2 screw and nut. Make sure the blade assembly is already inside of the rectangular hole before attaching the two pieces
• Check if the cutting works as expected by inserting some filament and then pressing in the arm
• Attach the whole thing to the top of the Neptune 3 Pro / Plus / Max extruder with M3 16mm screws to the backplate
• Snug fit the Filament_cutter_x_axis_bump_stop.stl onto the top of the X axis mount

NOTE: Purge bucket with nozzle wipe attachment coming soon

For how it would operate visually, DrawModelPrint has a video of his SEFC in action, end result is similar 

Combined the reverse bowden mount from Peaceman1995 and SEFC from DrawModelPrint on Thingverse. Modified to have better reliability