All Metal Upgrade?  

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cpmechengineer2
(@cpmechengineer2)
Active Member

Hi, I'm interested in buying an i3 MK3S with the MMU2 upgrade. I need to be able to print high-temperature and abrasive filaments as well as multiple materials (PVA, CF-reinforced nylon, unreinforced nylon); I understand there is a hardened steel nozzle available, and that E3D makes an all-metal version of their V6 hotend, which seems to be what the i3 series use; is that correct, and will it work with the MMU2 multi-material extruder?

Thank you!!

Posted : 12/06/2019 5:59 pm
gnat
 gnat
(@gnat)
Prominent Member

If it is a drop in replacement for the V6 then I don't see why it wouldn't. The one tricky part will be the heat break. If that hot end uses a different heat break and is not compatible with the normal one you may have issues.

The reason is that the Prusa V6 differs from the standard version in that it uses a modified heat break that has a step inside which is supposed to improve reliability of tip forming for the MMU. Without that heat break you (in theory) will not get as well formed tips which will lead to load/unload failures.

If you are looking to do high temps, I suggest looking in the MK3S forum for a currently active thread (I think it is in the hardware/software help section) about parts of the extruder melting under even normal PLA usage. For the type of printing you are talking about you might want to look into the BNB extruder upgrade or another that will be more reliable under such conditions.

MMU tips and troubleshooting...
Posted : 12/06/2019 6:14 pm
vintagepc
(@vintagepc)
Noble Member

The Mk3 /3S ships with the all-metal v6 version, with the exception of the custom heatbreak as noted above.

Posted : 12/06/2019 6:19 pm
Vojtěch
(@vojtech-p6)
Honorable Member

The good news is: The E3D v6 that is shipped with the Mk3S is the full-metal version already. No need to upgrade.

The bad news is: I couldn't find reports of success printing CF-reinforced nylon with PVA or BVOH supports using the MMU2S. The MMU2S has been reported to work well with PLA-PLA, PETG-PETG and PLA-PVA, but that's about it. You'll be entering untrodden territory. 

MMU2s, MK3S upgrade, and CF Nylon all are waiting on my desk to assemble and try. I've been printing CF Nylon nicely with the single-material MK3. For CF-reinforced PA6/6.6 copolymer nylons the only modification that's required is a hardened steel nozzle and PVA glue on the PEI sheet. PA12-CF so far resists my attempts to print it on the MK3 due to excessive warping.

This post was modified 1 year ago by Vojtěch
Posted : 12/06/2019 6:21 pm
gnat
 gnat
(@gnat)
Prominent Member

Heh. I was wondering just how much more metal could be added to it 😆 

MMU tips and troubleshooting...
Posted : 12/06/2019 6:25 pm
nikolai.r
(@nikolai-r)
Noble Member
Posted by: Vojtěch

... The MMU2S has been reported to work well with PLA-PLA, PETG-PETG and PLA-PVA, but that's about it. ..

No.. by far not :). My tests were done with PLA-PETG-ABS and it worked. So technically I don't see any issues why not add ASA, PC and Nylon to the list. It always depends what you want to print. The special properties of the material will be challenging like warping and not well sticking to each other. But the Printer itself should have no issues with combination of this material.

You're right in regards to the untrodden territory. There are not many use cases where it requires to combine those materials in one print.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram...
Posted : 12/06/2019 6:48 pm
cpmechengineer2
(@cpmechengineer2)
Active Member

Great info, thanks a lot guys.  Is there cocern that printing nylon and PVA/BVOh with the MMu2 may prove difficult due to the large temperature differences between the two, and the need to purge material without heating the PVA up to such a temperature that it crosslinks?  (If that's the only concern, perhaps one can play around with the prime tower settings and not allow it to heat up fully to nyln temperatures until it is thouroughly purged)

 

Thanks!

Posted : 12/06/2019 7:16 pm
nikolai.r
(@nikolai-r)
Noble Member
Posted by: cpmechengineer2

Great info, thanks a lot guys.  Is there cocern that printing nylon and PVA/BVOh with the MMu2 may prove difficult due to the large temperature differences between the two, and the need to purge material without heating the PVA up to such a temperature that it crosslinks?  (If that's the only concern, perhaps one can play around with the prime tower settings and not allow it to heat up fully to nyln temperatures until it is thouroughly purged)

Stock PrusaSlicer doesn't handle that issue well. But you can use this script and it solves the problem with the big temp difference.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram...
Posted : 12/06/2019 7:25 pm
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