Printing carbon fiber on a MK4s  

RE: Printing carbon fiber on a MK4s

Exactly the same as the others. Find a profile (check if Prusa has it in the configuration). If not, use a similar profile from another brand. If you are printing one small part, use a normal 0.4 mm nozzle (I do not recommend HF). If you are printing larger objects or multiple pieces, you must use a hardened nozzle (ObXidian).

RE: Printing carbon fiber on a MK4s

A 4mm nozzle will need a LOT of filament... 🙂 

I've printed many parts, including complete replacement sets of the plastic parts of my Mk4s, in PC-CF with 0.4 mm nozzles no problem.

You will need a hardened nozzle, I use Obxidian.

Prusaslicer has two profiles I have used, one for PC-CF and one for PETG-CF. Both worked fine without modifications. For PC-CF you definitely want to use an enclosure. And dry the hell out of it, and ideally run it out of the drybox. The difference between dried and not dried filament is profound.

Even for PETG-CF I used an enclosure, to keep any carbon fiber particles contained.

RE: Printing carbon fiber on a MK4s

After printing carbon fiber filaments, before reverting to print stuff without solid particles, I always perform a couple of cold pulls in order to remove any debris stuck to the internal walls of the  nozzle/heater block assembly. Best done with white PLA so it’s easy to spot black residues.  Sometimes, even two cold pulls in a row aren’t enough to get rid of all those carbon particles.

RE: Printing carbon fiber on a MK4s

Good idea to clean the nozzle, and I should have mentioned it because that's what I do too ! Instead of cold pulls I run a few lengths of cleaning filament at PC temperature through, which seems to work well for me.

RE: Printing carbon fiber on a MK4s

I wanna try to print MMU part in PETG-CF (i don't get enclosure to print them in PC-CF).

Do You recommand Obxidian HF or regular one's ?