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.
**After my holiday trip I will mount the toolhead for another proof of concept in the printer. Once this is done I would appreciate if someone with an working ERCF unit could check it.**
### Parts list - considering you already have a Stealthburner with Dragon Hotend
#### Toolhead:
- Loctite
- 1x M3 nut (DIN934; ideally 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 of ballpoint pen (L=15mm; D<=4,5mm) (I've ordered some for testing, to have a "defined" spring)
- Typ 4 Sharp Metall Skalpel (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)
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. !!**
