MMU2 - Real Multi Material  

RE: MMU2 - Real Multi Material

Posted by: @nikolai

Next step is to print the test object with ABS+PLA+PETG. I'm really excited if it can really work....

How did that work out?

I believe I have fixed this in PrusaSlicer. I want to run a test today before submitting a Pull Request to the PrusaSlicer repository. It took far longer to study and understand the code than to fix it. Fixing it was pretty simple.

My intended test is to print a PLA object that requires PETG supports.

However, I am confused about how to set the build plate temperature, when PLA requires 60°C and PETG requires 85°C. Does anyone have a recommendation about how to proceed?

RE: MMU2 - Real Multi Material

Actually that did work pretty well. Here is my test print attached ( I remember posted that somewhere already with the STL, but it's too long ago...):

Base (red) PLA, Windows (transparent) in PETG and columns in ABS.

RE: MMU2 - Real Multi Material

In case you just want PETG or PLA as support structure, I would go with the bed somewhere 65-70C. Most PETG hold already pretty well at this temperatures (also depends on your sheet).

RE: MMU2 - Real Multi Material

Posted by: @nikolai

In case you just want PETG or PLA as support structure, I would go with the bed somewhere 65-70C. Most PETG hold already pretty well at this temperatures (also depends on your sheet).

Depends on the sheet, indeed. I have a textured PEI sheet that has always been problematic. I've abraded it slightly with steel wool so PLA sticks better, which also caused PETG to stick almost too well. Perhaps the stickiness will still be OK for PETG at a lower temperature. I'll try 65°.

RE: MMU2 - Real Multi Material

Posted by: @anachronist

I believe I have fixed this in PrusaSlicer. I want to run a test today before submitting a Pull Request to the PrusaSlicer repository. It took far longer to study and understand the code than to fix it. Fixing it was pretty simple.

Woohoo! I finally got it working. The PrusaSlicer code wasn't easy to follow, and I had to visually examine g-code for a test cube with tool changes before I printed something for real.

Finally I printed my sailboat design, which requires supports for the sail. It came out beautifully with PETG supports. I had printed these before with breakaway PLA supports and it turned out OK, but not as good as this. I used the soluble-interface support configuration using these three materials:

• Prusament blue PLA for the boat hull and mast -- 215° first layer, 205° subsequent layers
• Prusament transparent PETG for support interface -- 220° first layer, 215° subsequent layers
• FilaCube bone-white PLA+ for the sail -- 220° throughout

All temperature changes happened as they should:

• When switching from 215° first layer PLA to 220° first layer PETG, the temperature got set to 220° while the PLA was unloading.
• Then after PETG printed two layers (at which time the temperature was reduced to 215°), it switched back to PLA at 205° but kept the nozzle at 215° until the PLA started purging out the old PETG (and the nozzle cooled quickly during the purge).
• Switching to the hotter white PLA+, the temperature was set to 220° as the PLA was unloaded
• Switching back to the cool PLA, the nozzle was kept at 220° until the purge started.

I had to be mindful of the fact that PrusaSlicer is intended to handle more than just the single-nozzle extruder + MMU configuration. It's being used for printers with multiple extruders also, and I took pains to make sure that this change affects only operation with the MMU.

In the attached picture, it is hard to see, but there is actually support material under the sail. This was printed with the "snug" support setting in PrusaSlicer.

Thanks to @Nikolai for the script logic, which I used as a guide for this.

Now I have to figure out how to raise a pull request to the PrusaSlicer repository.

RE: MMU2 - Real Multi Material

Update: I have fixed the wipe tower temperature issue in PrusaSlicer with this pull request but there's no telling if or when it will be included in a release.

RE: MMU2 - Real Multi Material

I am using PrusaSlicer 2.6.0 - and still have problems when changing from PETG to PLA. Looks like it is cooling down already while wiping PETG. But the jams definitly happens during load of PLA, maybe the extruder is still to hot. I have no problems with the change from PLA to PETG.

First question: Is your pull request merged in 2.6.0 - if not, how can i try this?

An other ideas how to fix?

RE: MMU2 - Real Multi Material

Is this something that would potentially work in new prusaslicer versions and with new MMU3? I'm not keen to the variables/parameters in such in the code to know if they are calling other parameters that are in the old slicer but now not in the new prusaslicer? I would try it but I don't want to royally screw up my slicer or printer without knowing for sure. Looks like it would be perfect for what I need though as I have been having issues with getting perfect tips on PETG.

RE: MMU2 - Real Multi Material

Posted by: @madcamper

Is this something that would potentially work in new prusaslicer versions and with new MMU3?

Yes, it still should work. This script does not have any gcodes to store any settings. So there is no harm to try it out.

It just changes the temperatures at the right time. All the configuration for the used materials are still happening in the slicer and being used by this script. 

RE: MMU2 - Real Multi Material

Great! I was looking through the script and not sure I see where to set the high temp and the low temp or does it do it based on the temperature set for said filament? I generally print PETG at 220-230 but that temperature causes too much stringing on the filament when it is retracted to the MMU. I've found that 203c appears to be the perfect temp(so far) to prevent any string strands on the filament when extracted to the MMU but printing the whole print at 203c causes lots of blobbing on the hot end. Sorry if it's mentioned somewhere but I couldn't find it.

RE: MMU2 - Real Multi Material

You set the temperature in the slicer. So if you set your PETG to 203C and PLA at 180C, it will use it accordingly. 

RE: MMU2 - Real Multi Material

When my mmu3 gets here I'll use that thanks so is it the same script sli3r uses 

RE:

Hi! I'm trying to print in TPU and make the supports in PLA. Is there a procedure you would recommend? Is the script still needed for the PrusaSlicer 2.6.1? The TPU part is a GoPro mount for my drone and some of it I would need to start printing midair so... Layer adhesion is very bad, most probably because of mixing TPU and PLA.

So far I found following things what I'm considering to test:

• script of @nikolai
• ramming
• buy a XL with double head instead of my MK3S+ with MMU2S

GoPro11 Mount Titan DC5 15° test.3mf

RE: MMU2 - Real Multi Material

Have you tried increasing the purge volumes during changes to tpu?

RE: MMU2 - Real Multi Material

Posted by: @maetthum

Is there a procedure you would recommend?

Hi. Even if I would like to see my script being used, it's not really needed in your case. 🙂

I would rotate this model by 180 degrees and print in TPU only. The sticky support for one leg can be easily cut off in post processing. TPU material is really easy to work with in post proc. 

RE: MMU2 - Real Multi Material

@joantabb

Just finished another test run. Increased purging volume for TPU on load to 300 and set the last layer to PLA support only. Now it seems to be allot stronger! Need to print the full model and pull on it again...

@nikolai

Sorry half of my TPU print was missing in the test file... this is the final below.

Any recommendations regarding post processing TPU if using TPU support? So far with a Stanley or carpet knife I'm not able to achieve nice looking surfaces. Supports stick just too well on the model 🙁

GoPro11 Mount Titan DC5 15°.3mf

RE: MMU2 - Real Multi Material

wow, you're braver than I ever was with the MMU.  I tried loading tpu exactly one time, and pretty much what I expected to happen did lol   This was on MMU2S which I don't think officially even supports doing TPU for obvious reasons(i.e. reliable filament loads/changes/tip shaping is hard enough on rigid filaments, let alone expecting it to work for tpu).  This is why I got the XL.   That actually does tpu multi material alright.

RE: MMU2 - Real Multi Material

so I looked at your model and I think I printed this once in straight tpu(in plain jane MK3S+) and I didn't like the artifacts left by the supports.   I was just curious how this would turn out on the XL so I'm trying one with Sainsmart tpu + PLA supports + BVOH interfaces.   This kind of use-case(tpu with supports) is of great interest to me since my wife likes me to print things in tpu and I kind it's been something I've been experimenting with over the past several days but using aquasys 120 as the support interface instead of bovh.

So far this is what it looks like.   I noticed I missed painting a couple supports, but so far it actually doesn't look bad.  471 tool changes with a 5h 16 min print time lol

Posted by: @ssill2

wow, you're braver than I ever was with the MMU.  I tried loading tpu exactly one time, and pretty much what I expected to happen did lol   This was on MMU2S which I don't think officially even supports doing TPU for obvious reasons(i.e. reliable filament loads/changes/tip shaping is hard enough on rigid filaments, let alone expecting it to work for tpu).  This is why I got the XL.   That actually does tpu multi material alright.

RE: MMU2 - Real Multi Material

Posted by: @nikolai

This is the next step towards the real multi material printing

I know this is an old thread. If anyone isn't aware, there's been a pull request for Prusa Slicer for over a year, that incorporates the logic described in this script. The PR is here: https://github.com/prusa3d/PrusaSlicer/pull/9737 - it's gone through some evolution since I created the PR as can be seen by the comments and the updates in the description.

You would think, now that the MMU3 is available, that Prusa would have some interest in merging this change into a release. But for now, you have to compile your own PrusaSlicer with the two updated files WipeTower.cpp and WipeTower.hpp.