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Chris
(@chris-23)
New Member
Force support shelf under soluble material

Hello,

Last night one of my prints nearly failed because the soluble material failed to stick to the regular support material.

 

  1. lower soluble material above part shell and below regular support worked fine;
  2. upper soluble material above regular support material failed completely

 

It is apparent the upper soluble layer failed because it did not have sufficient underlying material to stick to. In observation, the regular support appeared to move around a bit, the soluble layer a top it would fall between the gaps, and eventually the nozzle would pick up some of the soluble layer and drag it off the regular support.

 

Is there any way to force PrusaSlicer to make a 2-3 layer shelf out of regular support material directly beneath the soluble support layers?

 

Upper-soluble supports:

Regular support beneath the upper soluble supports:

 

The regular material was eSun PLA+, the soluble material is Verbatim BVOH. I have successfully printed other models with this combination in the past.

Posted : 04/12/2020 2:42 am
Vojtěch Bubník
(@vojtech-bubnik)
Admin
RE: Force support shelf under soluble material

> Is there any way to force PrusaSlicer to make a 2-3 layer shelf out of regular support material directly beneath the soluble support layers?

No, however it is on our radar.

...
Posted : 06/12/2020 6:35 am
bobstro
(@bobstro)
Illustrious Member
RE: Force support shelf under soluble material
Posted by: @vojtech-bubnik

> Is there any way to force PrusaSlicer to make a 2-3 layer shelf out of regular support material directly beneath the soluble support layers?

No, however it is on our radar.

I am going to be very happy if you guys are looking at supports! You've done an amazing job with everything so far, and my list of complaints & wishes list items for PrusaSlicer is shrinking every day.

I hope you'll spend some time looking at how ideaMaker does supports, particularly under large, flat surfaces. And of course, everyone wants Cura's trees. I'm looking forward to see what you guys come up with to improve things. Your implementation of ironing is stunning.

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 06/12/2020 6:47 am
Chris
(@chris-23)
New Member
Topic starter answered:
RE: Force support shelf under soluble material
Posted by: @vojtech-bubnik

> Is there any way to force PrusaSlicer to make a 2-3 layer shelf out of regular support material directly beneath the soluble support layers?

No, however it is on our radar.

Can you give an ETA? Is there a Github issue or PR for it that I can watch?

This is a frustrating showstopper for printing objects cleanly with soluble filaments, especially after all the work it takes to get the MMU2s itself to function.

Posted : 08/12/2020 1:29 am
david.w76
(@david-w76)
Active Member
RE: Force support shelf under soluble material

Rather than just having a flat shelf I wonder whether it would be even better to have the option of having some sort of multi layer geometric structure at the boundary between normal and soluble support to give the soluble support maximum chance of keying in and staying put.
Appreciate though that this would slow the print down a bit and use more expensive soluble support for the extra layers - but it may be worth it for the extra print reliability.

I guess it would be fairly easy to test different options by manually creating the standard material part of the support structure as extra shapes added to the print.

Posted : 09/12/2020 6:50 am
LauraWerner
(@laurawerner)
Active Member
RE: Force support shelf under soluble material

Has there been any progress on this? Earlier today I posted a nearly identical question in this forum before I found this thread. My PVA support interface (MatterHackers Pro PVA) isn't sticking well enough to the sparse PLA supports underneath it. A feature to create a dense "raft" of support below the support interface would be perfect.

Even if the new feature isn't implemented yet, any advice on getting better adhesion would be welcome. Are there settings I can mess with to make the PLA support more dense, or maybe support patterns that would make the two more likely to adhere? Right now I'm just using the defaults for the support settings because I'm fairly new at this.

Posted : 16/10/2021 1:31 am
Vojtěch Bubník
(@vojtech-bubnik)
Admin
RE: Force support shelf under soluble material

In PrusaSlicer 2.4.0-alpha3, the interface layers are split to the soluble and non-soluble layers. For example, with 4 interface layers configured, first two interface layers over sparse support are newly extruded with the base material, while the other 2 interface layers are extruded with the soluble material. This should resolve the issue of soluble interface not sticking to the base support.

BTW PrusaSlicer 2.4.0-alpha3 also implements snug supports as an alternative to the supports projected into a regular grid. The snug supports are similar in geometry to what Cura or Ideamaker produce. The snug supports may not work well with the split soluble / non-soluble interfaces, because splitting the interface islands into soluble / non soluble may make them too tiny to be filled reliably by FDM extrusions.

 

 

 

 

...
Posted : 16/10/2021 6:41 am
Vojtěch Bubník
(@vojtech-bubnik)
Admin
RE: Force support shelf under soluble material

In PrusaSlicer 2.4.0-alpha3, the interface layers are split to the soluble and non-soluble layers. For example, with 4 interface layers configured, first two interface layers over sparse support are newly extruded with the base material, while the other 2 interface layers are extruded with the soluble material. This should resolve the issue of soluble interface not sticking to the base support.

BTW PrusaSlicer 2.4.0-alpha3 also implements snug supports as an alternative to the supports projected into a regular grid. The snug supports are similar in geometry to what Cura or Ideamaker produce. The snug supports may not work well with the split soluble / non-soluble interfaces, because splitting the interface islands into soluble / non soluble may make them too tiny to be filled reliably by FDM extrusions.

 

 

 

 

...
Posted : 16/10/2021 6:41 am
LauraWerner
(@laurawerner)
Active Member
RE: Force support shelf under soluble material

Thanks! That sounds like exactly what I need. I'll give it a try as soon as I get my MMU put back together. (The idler cracked while I was trying various support techniques. Yesterday was not a good day.)

This will be the first time I've tried pre-release software from Prusa. How stable do your alphas and betas tend to be? At most of the software companies where I've worked, "Alpha" meant "Feature complete but full of bugs" and "Beta" meant "Still some bugs, but no (known) bad ones". Is that true for you guys too?

Posted : 17/10/2021 3:20 am
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