Problem printing PVA+ with Prusa MK3S (MMU2S)  

Active Member


I have a Prusa MK3S with the MMU2S upgrade. I'm trying to print very simple shape to see is the soluble filaments works. Here my settings in prusa slicer for the Prima Select PVA+


If I print only the supports (or the interface) with this settings the filament doesn't attach properly to the bed and the MMU say "MMU loading failed" and in some cases "MMU needs attention". So my idea is that on one side the filament settings are not correct. On the other side the printer has problems to problems to pull this particular material, maybe the filament buffer doesn't work properly (using 2 filament PLA works).


Any ideas?



This topic was modified 10 months ago 2 times by Simone
Posted : 19/05/2020 10:36 am
mik liked
Active Member

Here the link:

Posted : 19/05/2020 10:43 am
mik liked
Trusted Member

For people returning to this topic in the future, I did a bunch of tests with using PLA & PETG in same print and found that using different materials has a huge impact on model strength. For a typical purge volume of 250mm³ you can expect layer adhesion strength to be 1/5 of what it should be. Sadly only way to get around this is to purge crazy amounts of plastic ~2500mm³, or getting a 3D printer with at least two hotends
Posted : 28/07/2020 12:12 am
Active Member

Yep, pretty pissed at Prusa.  What a scam that sales video on youtube with that perfect dragon printed with soluble material using the MMU2S is.  I would love to see the 9000 hours of footage of them trying to get it to work.  Prusaslicer has presets for soluble interface layers, I bought the $100/kilo PrimaSelect from Prusa that says it works great with the MMU2S, I used the presets for that exact filament in Prusaslicer and it just curls up on the bed and gets stuck extruding.  I can only get one tool change out of it.  It will print the initial purge area in PVA, switches to PLA and prints in PLA, then tries to print in the PVA+ again and it just curls and doesn't stick to anything (neither to the bed or to the PLA then sticks in the extruder and won't unload.  Tried 4 times with no luck.  What is the point of presets if they don't work.  Don't put a setting in there for the exact filament you sell that doesn't actually work.  Really wish I had that $500 and 10 hours back from putting the MMU2S together and buying this scam PVA.  

Posted : 05/09/2020 6:56 pm
mik liked
Eminent Member

I have a similar problem when using PVA; I can get it to stick to the bed, get it to stick to PLA, get PLA to stick to it. The trick seems to be slowing down the print speed for PVA. The problem I have is the purge block.  I can't find any setting to let me change the purge speed of the PLA that comes after the PVA, and when PLA comes out just after PVA, there's a lot of PVA still in there (which is the whole point of the purge). It's that that starts peeling up and causing the print to fail. OK - I can just slow the speed of everything, but that's just getting stupid. I'm still looking around the settings, and I'm hoping something will become obvious...

Posted : 29/12/2020 5:51 pm

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