README.md

Enraged Rabbit "Filametrix" Filament Cutter

This options adds a lightweight filament cutting capability to the Voron Stealthburner CW2 toolhead for perfect filament tips without having to tune the traditional tip forming process. Thanks to contributors it supports a number of different hotends. This can lead to much greater reliability of your MMU. We hope over time to offer support for additional toolheads.

Illustration

Toolheads

Currently ERF is only available for the Stealthburner toolhead. We hope to offer other options in the future. When choosing toolhead sensors "types" refer to the explanation of options here.

Supported Extruders for StealthBurner and Sensor Options

Extruder	Sensor Option	STLs	Credit
Clockwork2 (CW2)	1_Toolhead_And_Entry_Sensors	Body	Credit: juliusjj25
	2_Toolhead_Sensor (EBB Board)	Body
	3_Entry_Sensor	Body
	4_No_Sensors	Body
LGX Lite	4_No_Sensors	Body	Credit: tommorox234

Supported Hotends for StealthBurner

Hotend	STLs	Credit
V6-R6 Repo	SB_V6_R6_Cutting_Printhead_Back.stl SB_V6_R6_Cutting_Printhead_Front.stl
Rapido Repo	SB_Rapido_TH_Cutting_Printhead_Rear.stl SB_Rapido_TH_Cutting_Printhead_Front.stl	Credit: juliusjj25
Dragon Repo	SB_Dragon_Cutting_Printhead_Back.stl SB_Dragon_Cutting_Printhead_Front.stl
Revo Voron Repo	SB_Revo_Voron_Cutting_Printhead_Back.stl SB_Revo_Voron_Cutting_Printhead_Front.stl	Credit: Russell Gower
Bambu Repo	SB_Bambu_Cutting_Printhead_Back.stl SB_Bambu_Cutting_Printhead_Front.stl SB_Bambu_Adaptor.stl SB_Bambu_Adaptor_M5_Nut.stl	Credit: Jakub Kadlec (Facebook)
Slice Mosquito Repo	Slice_Mosquito_Cutting_Printhead_Front_And_Rear.stl	Credit: MakeAUsername_285162

How it works

Proof of concept Video 1

Proof of concept Video 2

Filametrix in action

Note

• You will need to use one of the ADXL mounting threads
• Careful placement of the cutting point will minimize impact (if any) to build area. Note that a gantry servo option is available for operating the "Depressor Pin" to ensure no impact

What you need

Print list

Toolhead

• 1x SB (hotend name) Cutting Printhead Back
• 1x SB (hotend name) Cutting Printhead Front
• 1x SB Main body Cutting with ECAS (with selected sensors)
• 1x SB motor plate (as Stealthburner has seen a small update the newest plate does not fit anymore. So please use the one from this git)
• 1x SB Latch ECAS
• 1x Cutting Arm
• 1x Knife Holder

Cutting point on gantry

• 1x Depressor Mount
• 1x Depressor

Cutting point on gantry with servo

• tbd...

Parts list - considering you already have a Stealthburner with Dragon Hotend

Toolhead:

• Loctite
• 1x M3 nut (DIN934; idealy a countersunk tool to modify the nut for proper filament insertion)
• 2x M3 washer (0.5mm)
• 1x M3x18 SHCS (it repleaces the top left M3x25 SHCS from the SB-Cover mount)
• 2x Voron heat inserts
• 1x M3x18 FHCS (counter sunk screw)
• 1x M3x8 SHCS
• 1x M2.5x16 SHCS (15-18mm works)
• Spring 0.4x4x15 or alternative of ballpoint pen (L=15mm; D<=4,5mm) (I've ordered some for testing, to have a "defined" spring)
• Type 4 metal hobby blades (we will cut it to length) Link Amazon link, these need glue to be held in but work fine (USA) Link

Cutting point on gantry

• 1x M3x16 BHCS
• 1x M3 nut
• 1x M3x8 FHCS
• 2x M3 SHCS (Lengths: 6mm - no backers, 10mm - titanium backers, 12mm - MGN9 rails)
• 2x Voron heat inserts

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Assembly

Cutting arm

	Cut scalpel to length l=26mm
	After cut
	Insert scalpel into knife holder
Insert the scalpel (which is cut to 26mm) into the knife holder until you see it in the little hole. Use pliers to push it into the knife holder. Some force should be needed as the scalpel should stay in place due to the "pressfit". If that's not the case add some glue.(Depending on scalpel tolerances)
Put knife holder into cutting arm. The M2.5x15 screw is directly screwed into the plastic of the knife holder. The tip of the screw should be flush with the cutting arm or no more than 0.1-0.3mm above it. Check the orientation of the hole for the M2.5 screw in the knife holder. It needs to be on the bottom side.

Note

The knife holder must move up and down without friction in the cutting arm but shoult not have a lot play. Maybe some grinding is needed.

Toolhead Body

	Add heat inserts. Tip here for the heat set that goes above the cutter - suggest drilling the threads out with a ~2.5mm drill bit. On the hotend holder side below the cutter make sure you flare out the PTFE tube to help guide the filament.
	SB cutting Printhead back
	Depressor - one on either end, end with ribs should be flush with surface below ribs with no plastic sticking up past surface
	Finished cutting point assembly should look like this. Note: for titanium backers, the backer should be centered between belt clamps and the end of the depressor mount should be flush with the end of the backer. This will work for all backers with 10/20/40mm spacing with the furthest back hole 5-15mm from the end. Height of depressor should be adjusted to press in the depression on the cutting arm and the BHCS can be adjusted in and out for the right positioning and locked in place with the M3 nut

Happy Hare Setup

In mmu_parameters.cfg:

form_tip_macro: _MMU_CUT_TIP to instruct Happy Hare to use the filament cutter rather than normal tip forming.

Make sure toolhead_extruder_to_nozzle and toolhead_sensor_to_nozzle are set to your particular toolhead as per the Happy Hare documentation.

force_form_tip_standalone: 1 this tell Happy Hare to always use the tip cutting macro.

Important

Make sure you turn off tip forming or any extruder movements in your slicer - the slicer must not take any part in the filament swap. It should pick up when purging the new filament to the purge block.

In mmu_filamentix.cfg:

Configure the _MMU_CUT_TIP macro variables as per the instructions in the file.