Filament Cutter for Ender 3 v3 SE (Servo Motor Edition)

Change List:

04-25-2025
First upload

04-26-2025
I misunderstood the maximum current of MG996R and was connecting it to the ebb42 board, so it was temporarily drafted while I was fixing it.
(Thanks to the original author @matarsaed  for letting me know)

04-27-2025
Suddenly, the printer's cr touch broke down. Because of this, it was determined that normal testing was impossible and it was converted to draft.

05-02-2025 
sp_mmu.cfg(pico basic cfg):
1. I did a retreat to save the filament before cutting, but it was often jammed, so I commented it out
2. I judged that the retreat distance after cutting was insufficient, so I increased it a little.

05-03-2025 #1
Modify (commented) retreat part before slicing. 
In my case, a little extrusion before retreating solved the nozzle clogging problem a little

05-03-2025 #2
Added GEAR_FIT_HOLE
After some use, found that the GEAR parts do not mesh properly with the servo motor. Either fix them to the existing GEAR model with glue gun or bond, or use the FIT_HOLE model.

05-05-2025
Added step files


Requirement:

##################################################

The site where I purchased the MG996R only indicated the operating power as 1A, but after checking overseas sites such as AliExpress, I confirmed that it can use up to 2.5~3A. 

Thanks to the original author @matarsaed  for letting me know.

This modeling used MG996R, but if you want to use this motor, you will need a 2A~3A voltage step-down module or an external power source. 

Since the maximum power used in the MG996R stall state is 2.5~3A, if you have a filament that is not too strong and have assembled it perfectly, it may seem okay to use only 1A of power for now, but be careful because the board may turn off or break down later.

###################################################

180° high stall torque Servor motor(Maximum Current 1A, 5V)

or MG996R + 5V  2~3A External Power(or Step-Down Converter)

3M(x6 or more longer&nut ) screw * 4

Assembly:

Wiring

EBB42 V1.2 with 

Maximum Currnet ≤ 1A servo motor:

Maximum Current > 1A servo motor:

(image source: https://github.com/lhndo/LH-Stinger/wiki/Pico-MMU#klipper)

Add cutter.cfg in your klipper
 

---------------------------------------------------------------------------

cutter.cfg:

[servo cutter_servo]
pin: PICO_MMU: PB3    # Servo pin
initial_angle: 0
maximum_servo_angle: 180
minimum_pulse_width: 0.0005
maximum_pulse_width: 0.0025

[gcode_macro CUTTER_ON]
gcode:
   SET_SERVO SERVO=cutter_servo ANGLE=180

[gcode_macro CUTTER_OFF]
gcode:
   SET_SERVO SERVO=cutter_servo ANGLE=0

[gcode_macro CUTTER_SLICE]
gcode:
   CUTTER_ON
   G4 P2000
   G0 E-{5} F{500}   
   CUTTER_OFF
   G4 P1500

---------------------------------------------------------------------------

add
[include sp_mmu.cfg]
in cutter.cfg
 

After turning on the printer, run the "CUTTER_ON" macro

Then turn off the printer (the CUTTER should remain “CUTTER_ON” mode)

Attach the blade to the CUTTER and assemble it to the “BASE”

Then attach the BASE to the extruder.

Next, assemble the extruder motor.

In the photo it says "Insert CUTTER part" but after checking again now it seems like "Push CUTTER part" is a more accurate expression.

Open the sp_mmu.cfg file in Clipper and modify the [gcode_macro _SP_TIP_FORM] section as shown in the picture.
 

--------------------------------------------------------------------------------

[gcode_macro _SP_TIP_FORM]   ## Tip forming user macro called during the tip forming procedure  - Filament Cut Macros go here

gcode:    

  # G0 E3 F300 # If you want retreat before slicing,  remove # at the beginning (recomand dist: 1~3)

  # G0 E-35 F600 # If you want retreat before slicing,  remove # at the beginning

  CUTTER_SLICE

  G0 E-30 F600

  # _SP_TIP_FORMING   ## Built-in tip forming macro - replace with your own if needed

--------------------------------------------------------------------------------
 

If you didn't do any retraction work right before cutting, you'll need to modify the meltzone distance&speed variable settings.

The pictures below are my personal settings, so please refer to them.

(I set the cold zone speed low)

~DONE~

Actually, I just finished it so I haven't used it much yet.

If there are any inconveniences while using it later, I will come back and fix them~

The printable area is increased by removing the filament using a servo motor.