Filament Cutter for Ender 3 V3 SE/KE

🔄 Changelog

Update 20.05.2025
Added support for servo stopper: new file Servo_Stop v1.stl, instructions below.

Update 13.04.2025
Increased the width of Lever Pusher by 1 mm to prevent it from falling out during operation. This should fix the issue some users experienced with loose fitting.

Update 03.04.2025
For users who encountered an issue with filament not properly transitioning from the extruder to the heatsink—resulting in the filament sticking at the heatsink entrance after modifying the PTFE tube—I’ve now added a base with a filament guide (Cutter_Base with guide v1). 
 

📄 Overview

This is a lever-operated filament cutter designed specifically for the Ender 3 v3 SE. The blade is positioned between the extruder and the hotend, allowing you to cut the filament right near the hotend. This setup is especially beneficial for multi-material (MMU) printing or frequent filament changes, as it helps maintain a clean filament tip and reduces the risk of clogs during tool transitions.

🧩 Parts List

1. Cutter_Base
2. Cutter_Lever
3. Blade_Spring_Insert (slides inside the base)
4. Cutter_Lever_Insert (or Lever_Pusher)
5. (Optional) Cutter_Stop (if used in your design)
6. (Optional) Servo_Stop (servo stopper variant – replaces static stop)

🔧 Additional Hardware

• (1) Snap-off blade segment (18×100 mm, 0.5 mm thick – standard utility knife blade).
  
• (2) M3×8 mm screws (for mounting the base; (optional) extruder already holds it firmly).
• (1) M3×25 mm screw + (optional) Heat Insert (to secure the Cutter_Lever to the Cutter_Base).
• (1) Small compression spring (commonly found in ballpoint pens).
• A small plastic spacer or a short piece of filament can also be used to help secure the pivot for the Lever and Lever_Pusher.

🖨 Printing & Post-Processing

• Material: PETG or ABS recommended for durability; PLA can work but may wear out faster.
• Layer Height: 0.2 mm is a good start.
• Infill: 35%–50 % (Gyroid).
• Supports: Likely needed for certain overhangs (depending on print orientation).
• Cleanup: 
  - Make sure to remove any stringing or bumps that could obstruct the Blade_Spring_Insert.
  - The Blade_Spring_Insert should slide smoothly within the Cutter_Base. Minor sanding or filing may be needed on any friction points.

🧱 Assembly Steps

1. Insert the blade and spring:
   Blade: 
   - Snap off a segment from a standard utility knife blade (18 mm wide, 0.5 mm thick). 
   - Place it into the Blade_Spring_Insert (or whichever part holds the blade in your design).
2. Spring (from a pen):
   - Use a small compression spring from a ballpoint pen.
   - Ensure the spring stays in place and doesn’t bind or interfere with the sliding action.
3. Combine the Insert and Base:
   - Slide the Blade_Spring_Insert into the Cutter_Base.
   - Ensure it moves freely when pushed.
4. Attach the Lever_Insert:
   - The Lever_Insert (or Lever_Pusher) goes inside the lever. It presses against the Blade_Spring_Insert.
   - Secure it with a short piece of plastic or leftover filament as a pivot pin (or use a small screw if you prefer).
5. Mount the Base to the Printer:
   0 Use two M3×8 mm screws, or rely on the existing extruder mounting pressure to hold it in place.
6. Mount the Lever:
   - Attach the Cutter_Lever to the Cutter_Base with an M3×25 mm screw.
   - Optionally use a heat insert or a simple nut.
7. Test:
   - Manually depress the lever to ensure the blade moves correctly and slices through a test piece of filament.
   - Make any final adjustments or sanding if it binds.

💡 Tips & Notes

Safety: The blade is sharp! Handle with care.

Lubrication: A dab of PTFE-based lubricant can help the Insert slide more smoothly.

Maintenance: Over time, the blade may dull or the plastic may wear—just replace the blade segment as needed.

🤖 Servo Stopper Integration

This update introduces an optional servo-based stopper mechanism, which replaces the static physical stop. Unlike the static version, the servo variant operates entirely outside the active print area and does not interfere with the usable bed space.

Required components:
– Servo_Stop v1.stl – updated cutter body (included in this project)
– Servo Mount v2.0.stl and Servo Arm V2.0.stl – available here:
👉 https://www.printables.com/model/1097275-voron-24r2-filametrix-filament-cutter-gantry-servo

Note:
Both external files must be mirrored before printing to be compatible with this cutter design.

For setups using PicoMMU, you can contact me directly on Discord: matarsaed
or join the community at: https://discord.gg/EzssCfnEDS – I’ll be happy to help with integration if needed.