Soluble Supports  

Filament Settings > Advanced > Filament properties

Print Settings > Support material > Options for support material and raft > Top Z contact distance

- or use one of the predefined soluble interface Print presets.

Cheerio,

RE: Soluble Supports

I'm guessing you have an MK4? For some reason, the PVA and BVOH profiles aren't on the MK4 with MMU3 profile. I looked in PS for Verbatim BVOH and it said it was compatible with the MK3S+ and MK4 IS profiles I have, but the 3rd profile I have, MK4 MMU3, was not listed as compatible and the filament had a *, which indicates not compatible with some profiles.

I don't have a profile for MK3 with MMU installed on PS, but it seems the soluble material options aren't available on the MK4 MMU3 profile yet. I am looking into this myself due to a Reddit post I saw this morning, and because I plan to do PVA+ support interface on my own prints in the near future. The only thing I could find on PS with the MK4 MMU3 profile was to go to Print Settings > Multiple Extruders > Extruders and then adjust the listed extruders for support material/raft/skirt extruder, support material/raft interface extruder, and the wipe tower extruder. By setting the support material extruder to 1, and support material interface to 5, and slicing, the slicing result screen showed that it had the soluble interface printed. Didn't solve putting the PVA+ filament profile into the MK4 MMU3 profile, but I'm guessing that wouldn't be super difficult to do, with some tweaks like increasing the temp the same way PLA profile temps went up 20 °C from non-IS to IS profiles.

RE:

That is what I tried too, but the slicer won't allow you to indicate extruder 5 for a different material (ie soluble). As soon as you then set the "raft interface extruder, and the wipe tower extruder" to anything other than 0 you get the warning sign that the wipe tower doesn't support it and it turns it off. 

Very disappointing as this has set the functionality of the MMU back from going from MK3S+/MMU2 to the MK4/MMU3. Hopefully Prusa will quickly remedy this by publishing more configurations for the MK4 & MMU3 so that soluable supports and multiple material printing are actually possible. 

RE: Soluble Supports

Interesting. I had this exact same conversation on Reddit and that person told me the same warning you got. Except I didn’t get the warning.

What OS are you running PrusaSlicer on? I’m running it on Linux, with the AppImage. I wonder if that is causing the issue. A difference in behaviors, perhaps a bug, between OS releases.

RE: Soluble Supports

Huh. That’s it. I fired up PrusaSlicer on Windows and got the warning, and it won’t let me use the wipe tower if I change extruders.

But it lets me do it on the Linux version of PrusaSlicer, with no issues!

That explains why the person on Reddit downvoted me when I said how to do it with exactly what I outlined (and tested!) here.

So is it a bug that the Windows version doesn’t allow you to do different materials with the wipe tower enabled, or a bug that the Linux version does allow you to do different materials with the wipe tower enabled?

RE: Soluble Supports

I’m using the Mac version and there also no luck. Seems that only the Linux version supports this then?

Strangely, though, the warning about the wipe tower not supporting this is so specific that I find it hard to accept that it’s a bug. 

RE: Soluble Supports

Update! We missed something! My conversation on Reddit continued, and you have to set the Print Settings > Support Material > Options for support material and raft > Top contact Z distance to "0 (soluble)"

Then the warning changes to "For Wipe Tower to work with soluble supports, the support layers need to be synchronized with the object layers. Shall I synchronize support layers in order to enable the Wipe Tower?"

And then it works on Windows version of PS just like Linux version! I forgot, I must have set that distance to 0 as my first attempt to get it to work, and forgot I set it to 0...

Hopefully that works for you!

RE: Soluble Supports

Thanks for the help everyone.

After looking into this more.....it seems that we're still waiting for Prusa to add a Soluble Supports Profile for the MK4 (along with Verbatim BVHO filament profile).

In the meantime, I can add the MK3 profiles to my computer and try to hack the Mk3 profile and use it for the MK4.

I would have figured that the half-year they were trying to make the MMU3 work on the MK4 that someone would have updated the software profiles.  LOL.

Thanks again everyone!

Eboman

RE:

Hi all –

I had a bit of time these last two days and studied this some more. I now have two good Print Settings on PrusaSlicer for the MMU3 0.4 nozzle: one for soluble supports and one for just soluble interface layers. Here's a short manual to add these Print Settings. With it you can easily add them for any of the other nozzle sizes. 

First: Make sure you have the MMU3 presets installed (click cartwheel next to "Printer" and select 'Add/Remove presets'. Then make sure that under MK4 Family, you have checked the box under "Original Prusa MK4 MMU3" - "0.4 mm nozzle". Then, press Finish and select this printer in the printer list. I made a copy of this setting which you can do easily by going to the "Printer Settings" tab and change a parameter. I selected each of the Extruders from the list on the left and changed the Extruder Color parameter to "Reset to Filament Color". Once you've done that, click the "Save Preset" icon and save it. Feel free to change the name.

Now, go to the "Print Settings" tab and select in the Print Settings box at the top "0.20mm STRUCTURAL @MK4IS 0.4". Then, click the "Save Preset" icon to save a copy of these settings. At the words "SOLUBLE FULL" or something similar to the name so you can recognise it for what it is later. Then, change the following parameters:

->> Important: Make sure you save the changes on every screen: If you change screens, for instance from ‘Layers and perimeters’ to ‘Speed’ without saving, your changes are lost. <<-

• Layers and Perimeters -> Quality -> Thick Bridges -> Check
  I actually think that this is not really necessary but when I checked the MMU2 settings on the MK3, this was set for the soluble printer settings. I can't think of a situation where a support material forms a bridge. But, hey, if it doesn't matter, we can just as well turn it on, right? 😀
• Support Material -> Support Material -> Generate Support Material -> Check
  Ehh, yes, that's the whole point, isn't it? When we use this Printer Setting we've already decided we need support material to be generated. 
• Support Material -> Support Material -> Overhang threshold -> 70
  This means that supports are generated when the overhang is 20˚. I thought this is was a little confusing but according to Prusa, a printed vertical wall is defined as having an overhang of 90˚. Intuitively I'd say this is 0˚ because the wall is not 'overhanging' because it's, well, vertical and straight. Anyway, normally you would generate support material for anything that is more than 45˚ overhanging. The default threshold setting for MK4IS is actually 40˚ (in Prusa terms) which is an overhang of 50˚ or more. The reason we want to use soluble material is that we want absolutely smooth structures which means we need supports with only the slightest overhang. Setting this threshold to 70 means that with an overhang of 20˚ we already have support materials. If you want you can set this threshold even higher to 80. 
• Support Material -> Options for support material and raft -> Top contact Z distance -> 0 (soluble)
  By setting this parameter we tell the slicer to ensure that the top layer of the support material interface is exactly the right height for the overhanging structure to be printed on. With non-soluble support material you want to add space which makes it easier to remove the support material. In that case the first layer of the object printed on top of the support material will be printed with bridge flow and look somewhat different from the rest of the print. With setting the Top contact Z distance to 0, this is not necessary and you get an even print of your object.When you set this parameter, you may get a warning window popping up telling you that for the wipe tower to work the support layers need to be synchronised with the object layers. If you get this window, click 'Yes' and this setting will automatically be adjusted.
• Support Material -> Options for support material and raft -> With sheath around the support -> Check
  Checking this option will tell the slicer to wrap the support material in a thin wall. This will make the support a lot stronger and for the setting whereby the full support material is made of soluble filament and not only the interface layers, this is strongly recommended.
• Support Material -> Options for support material and raft -> Top interface layers -> 2 (default)
  I’m going with the default of 2 layers here, but if you want you can change this to 3. Anything higher is not really necessary, but I’d recommend against only 1 layer.
• Support Material -> Options for support material and raft -> Bottom interface layers -> Same as top
  You can choose 0 here if you use ‘support material from build plate only’. Otherwise it makes sense to use the same setting for the top interface layers. I think it is highly unlikely that you would go through all the trouble of using soluble material but choose to not use it for overhangs that are not directly above the build plate.
• Support Material -> Options for support material and raft -> Interface pattern spacing -> 0.1
  This is the space between the lines of the interface layers. When set to 0 you get a solid surface. Recommended setting is 0.1 mm. This doesn’t affect the quality of the first object layer but it makes it easier to dissolve the interface layer.
• Support Material -> Options for support material and raft -> XY separation between an object and its support -> 40%
  This setting determines how close the support material is printed next to the object. Standard setting is 80% of the width of the external perimeter of the object and that is probably fine. With the use of soluble support material I usually go a bit closer as the only drawback is that it would be more difficult to separate the support material from the object, but with soluble that make no difference.
• Support Material -> Options for support material and raft -> Synchronise with object layers -> Check
  This setting was automatically checked if you clicked ‘Yes’ when you got the warning about the wipe tower when you set the Top contact Z distance to 0 earlier. If it isn’t checked, please do so now.
• Speed -> Speed for print moves -> Support material -> 25
  Both PVA and BVOH are sensitive materials and break easily when heated (ie during printing). The manufacturers recommend a slow printing speed and that is what is set here. Instead of the default MK4IS speed of 120 mm/s for support material, I recommend to use the setting for 25 mm/s.
• Speed -> Speed for print moves -> Support material interface -> 80%
  The interface layers must be perfect to avoid any issue with the first object layer print. Therefore I recommend to slow the printing even further down to 80% of the speed of the support material printing.
• Multiple extruders -> Extruders -> Support material/raft/skirt extruder -> 5
  With this setting we indicate that the soluble material will be loaded as the 5th filament on the MMU3, and that that filament should always be used for all support materials.
• Multiple extruders -> Extruders -> Support material/raft interface extruder -> 5
  Similar as the previous setting only that this sets that the 5th MMU3 filament shall be used for all support interface layers.
• Advanced -> Extrusion width -> Support material -> 0.45
  This gives the support structure more stability and strength which is a good thing!
• Dependencies -> Profile dependencies -> Compatible printers condition -> printer_notes=~/.*MK4MMU3.*/ and nozzle_diameter[0]==0.4 and num_extruders>1
  When you modify these Printer settings will only be selectable when the MK4 plus MMU3 printer setting is selected on the Plater tab. When you make these modifications for different nozzle sizes, don’t forget to modify the 0.4 in this text to the actual nozzle diameter size.

 Provided I haven’t made a mistake in any of the above, you now have Printer Setting option for soluble supports when you select the “Original Prusa MK4 MMU3 0.4 nozzle” printer from your list.

If you only want the interface layers to be soluble and not the rest of the supports, you can make another Printer Setting specifically for this. To do this, first make another copy of these Printer Settings and save them with a new name, for instance with the word “INTERFACE” in it. Then, you need to make changes to the following settings:

• Support Material -> Options for support material and raft -> Top interface layers -> 3 (heavy)
• Support Material -> Options for support material and raft -> XY separation between an object and its support -> 80%
• Multiple extruders -> Extruders -> Support material/raft/skirt extruder -> 0

The last thing to do is to add your soluble filament to the list of available filaments with all the right settings, and select it as the 5th filament in the list of filaments on the Plater screen.

Let me know if you have any questions and I’d love to hear your feedback, particularly if you have any suggestions to optimize any of these settings.

Thomas

RE: Soluble Supports

Very cool !!!

Thanks Thomas.  I appreciate you taking the extra time to lay this out for all of us.

Again, it's a shame that Prusa hasn't gotten around to doing this yet.  It's actually showing in their Manual that it's already a Preset.  Like you've shown, it's not a difficult or time-consuming Profile to make for the MK4/MMU3.

I've always been a big Prusa supporter/fan.  Over the past couple of years, I've been into Resin 3d Printing more than FDM.  However, the release of the MK4/MMU3 have brought me back to filament printing in my spare time.  It still sometimes amazes me how "slow" the Prusa team can be to update existing software/products.  

But they sure are "quick" to take my money by announcing/selling new stuff (and then delaying the release/ship dates indefinitely).  hahaha

Thanks again everyone!!

Eric

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