I was looking at the ERCF MMU for several month now. What always kept me from starting the project were the discussions about issues and problems with filament tip forming. Suddenly a new company showed us how they do it quite reliable. They just cut the filament. Further motivated and inspired by the design of @pure100kim who has built the [ERCF_Filament_Cutting_MOD](https://github.com/pure100kim/ERCF_Filament_Cutting_MOD) I started to build my own version of it.
## See how it works
Proof of concept 1: https://youtube.com/shorts/HOMG8cVk_U4
Proof of concept 2: https://youtu.be/tTcrxttyths
Filametrix in action: https://www.youtube.com/watch?v=tfMZWQRqtvY
## Good to know
Please be aware:
- We will need to use one of the ADXL mounting threads
- Depending on the setup and position of the cutting point we will most probably not lose any build volume
- For the main body i remixed the ECAS version from [Alexanderor](https://www.printables.com/de/model/433797-clockwork-2-ecas-fitting-for-ercf)
## Extruder and Printhead options
### Extruder
#### Clockwork2 Extruder
Due to recent changes in the Clockwork2 design (July 2023) two motor plates exist, please check carefully which version you are using and print the corresponding main body.
- SB_CS2_Main_Body_EBB_ECAS_D2F "CW2 main body for the ERCF w/ ECAs, bearing switch, and SB2209 Canbus mods" Thanks to [juliusjj25](https://github.com/juliusjj25)
Additonally, a more rigid [latch](STL/[a]_latch_M6.stl) is available for the M6 version. (ECAS version of the latch is compatible with all M6 main bodys.)
- Type 4 metal hobby blades (we will cut it to length) [Link](https://de.aliexpress.com/item/1005005117830095.html?spm=a2g0o.order_detail.order_detail_item.9.47c26368QwSbBr&gatewayAdapt=glo2deu) Amazon link, these need glue to be held in but work fine (USA) [Link](https://www.amazon.com/dp/B07QP8L1QG)
Insert the skalpel (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 skalpel should stay in place due to the "pressfit". If that's not the case add some glue.(Depelding on skalpel tolerances)
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.
**!! 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. !!**
Tip here for the heat set that goes above the cutter I would 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.
#### 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.
You will need to adjust the parameters in addtional as well, like setting up your cutter location, speeds, etc. More information in the cfg file itself.
set variable_output_park_pos: ... to the distance from the nozzle tip to the blade
The _MMU_CUT_TIP now has an option to move to a "next location" immediately after making the cut. For instance, set it to the purge tower's location from the slicer. The _SET_LOC_AFTER_TOOLCHANGE sets this location, and the _MMU_CUT_TIP macro will be responsible for traveling immediately after the cut but prior to the unload. See the orcaslicer's toolchange gcode two messages down as an example. If you don't plan to use it, it's safe to ignore this point.
