How to improve handling of Soluble Support Material on MMU2s - What is your experience?
Dear All,
The main reason why I bought the MMU2s upgrade was because of the possibility to include soluble supports. I was warned by the red red flags in many forums about this upgrade, but the possibilities were so many that I gave it a shot.
So far I have worked with PLA, and in my hands when using only PLA my results have been very good, and I cannot complain too much. Prints of 9h typically require me to make only a couple of interventions, but sometimes the printing goes on without incidents. With respect to the use of PLA I am very happy with the upgrade, multicolor is great and I would say it was a good investment.
It is with the handling by the MMU2s of the PVA from eSUN that I got really disappointed. eSUN is a brand I have used on multiple occasions, and the results are typically rather good, and their PVA filament is said to be on the better lot.
Using a freshly opened vacuum-sealed PVA spool, I had some initial problems of the filament at the extruder, but within two days of troubleshooting and studying these were resolved by adjustment the Idler tensioning screw and tweaking some settings in Prusa Slicer to account for the oozing (particularly high retraction distances and speeds were important). After this bottleneck was passed, all that remained were problems with the MMU2s unit that would not handle the eSUN PVA filament reliably. Filament load and unload failed constantly. From my experience at failing with the PVA from eSUN i got the impression that the material properties of the filament are not adequate for the hardware configuration of the MMU2s. The reason seems to rely on the mechanical interaction between filament and the Bondtech gears. Using the same MMU2s filament inlet with PLA filament results in no issues whatsoever. Adjusting the tensioning screws did not seem to reliably resolve the problems either.
I have now ordered some BVOH from Verbatim in hopes that this would be better. I will be posting here my experience once I have some further news.
In the meantime, it would be nice to know also some success stories, and if you had problems only with some filaments and not others, if success depended on the type of soluble support or if brand was relevant in your case. People often tend to voice their discontent, but it is important that people with positive experience (even if partial) to jump in. Unfortunately Prusa seems not to be handling this situation well enough and it would be nice to have some definite input from them too.
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
I also bought the MMU2S mainly to be ready if I need soluble supports. I also have a sealed spool of Verbatim BVOH ready.
The thing is, I don't currently have any models in the do-it queue that need such supports, and I have enough planned to keep the printer busy for at least the next month or so on the model railroad project.
I normally have the MMU2S disconnected, electrically with a mounted switch and mechanically with the extruder tube disconnected. However, I have run it in both the single filament and multicolor modes and I'm confident that it will consistently load and unload reliably.
Now I just need a model to test it out. 😉
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
So yesterday I tried for the first time some TPU (eSUN, A95). It is considerably less stiff than PLA, making it with respect to this more similar to PVA filament from eSUN. The MMU2s unit seemed to handle that much better than PVA - my BVOH is coming tomorrow, I'm really crossing fingers here!!
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
I forget which PVA I have, but I found the attempts to use it to be rather miserable.
- I had to resort to desecrating my smooth plate with glue stick to get it to stick to the plate.
- As my setup is not enclosed and humidity controlled I found I had to keep stopping the print and running the PVA through my dehydrator every 2-4 hours for 4-6 hours.
- As the filament picked up moisture it got more and more stringy which resulted in clogging up the FINDA.
- Even with incoming and outgoing purges set to 200 it was clear that there was still bleed between the PVA and PLA.
- After manually removing most of the supports, after soaking for 24 hours most of the remaining supports were still there.
I hear that BVOH is supposed to work better, but I think I'll play with mixing PLA and PETG to support each other instead.
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
@gnat
The best tip I have is to limit the soluble support to a single layer between the object and traditional supports. That will save you some money on support material and limit the amount of time the PVA is being handled. Also, try to make a dry box for your PVA, it helps a lot.
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
I used the alternative ramming profile posted here on the forum a long time ago (much faster, longer but also with more cooling cycles, a wild mixture indeed which only works in its combination). The tips it creates look a bit uglier than the standard settings but it is much more robust against stringing tips especially with material that tends to end up getting terrible after several hours of print.
I could print an entire upside down Benchy without a single loading failure that way, using BVOH from Verbatim. The Benchy is now next to the traditional ones and if you don't look closely it is hard to see that it was printed upside down with solube support.
PS: I'll have to look up the precise settings.
Mk3s MMU2s, Voron 0.1, Voron 2.4
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
Those were the settings I think I used for the BVOH. I think for BVOH I used 5 cooling moves, for the other filaments the same settings but 4 cooling moves.
Loading speed at the start: 19 mm/s
Loadin speed : 14 mm/s
Unloading speed at the start: 140 mm/s
Unloading speed 90 mm/s
Filament load time: 15 s
Filament unload time 12 s
Delay after unloading 0 s
Number of cooling moves: 4 (or maybe 5)
Speed of first cooling move: 20 mm/s
Speed of last cooling move 10 mm/s
Ramming setting:
Change "total ramming time (s)" to: 4.5
Mk3s MMU2s, Voron 0.1, Voron 2.4
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
Something I found is that printing with multiple materials (not multiple colours of same material) leads to weaker layer adhesion, unless you do crazy volumes of purging:
https://www.antalife.com/2020/07/project-just-how-multi-material-is.html
Also here are some general upgrades I did to my printer to improve reliability:
https://www.antalife.com/2020/07/project-prusa-i3-mk3s-mmu2s.html
www.antalife.com
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
my experience dont want you to know .
worst machine a bought . mmu2s is a betta product... is performing very poorly , want my money back
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
Antalife, some here have reported that PLA and PETg adhere to each other so poorly that one can be used as a break-away support material when printing with the other.
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
I just started with soluble filaments few days ago (I ordered a spool of Verbatim BVOH and PrimaSelect PVA+).
The filament is coming directly from a spool dryer where the spool is placed.
So far the experiments with PrimaSelect PVA+ have been miserable. The filament is very fragile and ends up breaking during filament change, most of the time in the tube between the MMU2S unit end the extruder. The filament was taken out of the box and immediately put in the filament dryer therefore I rule out moisture contamination.
I just started my first test print with the Verbatim BVOH and after 45 minutes of printing no failures so far.
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
@lvet
Did you need to tweak any parameters in order to print with BvOH?
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
@rhjpires,
I used the default settings for Verbatim BVOH. Of course, reading about the adhesion problems, I thoroughly cleaned the smooth PEI sheet with water and dish soap.
Eventually my small tests printed really well. I tried both the "soluble interface" and the "soluble full" presets. I think that using the "soluble interface" is wiser as most of the BVOH will be printed on top of fresh PLA rather than the PEI sheet.
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
@jsw
Yea printing with those two is not an issue, I am talking about contamination of one material into the other. For example you print body out of PLA and supports out of PETG (or PVA or BVOH...), with a single extruder printer it's incredibly hard to fully purge the old material to the new. Basically leading to contamination of PLA with PETG, worsening the layer adhesion of the main body
www.antalife.com
RE: How to improve handling of Soluble Support Material on MMU2s - What is your experience?
What one needs to keep in mind is, that when you mix materials, problems with stringy tips might phase in (in need of better words) only slowly, over several hours if you have soluble filaments used at every layer. So short prints might actually work fine but proper prints of a 24h or more print duration will be riddled with increasingly stringy tips. At least that's the experience I had.
Mk3s MMU2s, Voron 0.1, Voron 2.4