Alternate extra wall, with multiple extra walls, and maybe repeating over 3 or 4 layers not 2

[r111122223333 0]

Is there a way to do this? I want to use alternating wall count functionality, but I want to add say 2, or 3 or even 5 extra wal (perimeter) lines on every alternate layer, not just one extra line on alternate layers. I'd also be interested in doing this not on alternate layers but instead on every Nth layer (third or fourth perhaps). Also, would there be any way to make this apply only to inner walls, while just leaving a fixed wall count on outer perimeter walls.

Thank you

P.S. ideally there might be a way to do this in version 4.11? I'm on Linux and I don't think my versions graphics "drivers" are too happy with Cura versions more than a few releases after 4.11, trying to install 5.x might involve lots of nasty dependency hell with my OS before I could begin

Edited May 28 by r111122223333

[GregValiant 1,112]

"I want to add say 2, or 3 or even 5 extra walls (perimeter) lines on every alternate layer, ..... on every Nth layer...?"

There are no settings to do something like that.

You can alternate a single extra wall  I think that thought behind that is to trap the infill at the walls.

"...apply only to inner walls, while just leaving a fixed wall count on outer perimeter walls."

I'm not sure I understand that one.  I'd say that because the answer to the first question is no, that this one doesn't come into play.

Wouldn't 5 extra walls every 10th layer result in those extra wall extrusions being printed over air?  You would need pretty high infill density to hold them up.

[r111122223333 0]

I want to try this as a way of eliminating touble I am getting with the walls on small (2mm to 4mm) internal circular holes not properly adhering to the main infill. NOTHING I've tried from commonly recommended settings changes has worked thus far, and a single alternating wall isn't enough to properly overlap the infill with the inner walls and anchor them together. And that is even with having massively increased the overlap percentage settings.

 

I do tend to use fairly high density infill, so 5 extra perimeters every 10th layer would work fine for me, though what I'd initially want to try is 3 extra perimeter walls (for inner walls only) every second layer.

 

Having multiple perimeter walls alternating should give a much better trapping of infill (especially high density infill) than a single alternating wall can, and should help combat any shrinking of the hole walls which might be the reason they pull away from the main infill, see this:

https://www.eevblog.com/forum/3d-printing/under-extrusion-around-the-edges-of-circular-holes/

 

Thank you

Edited May 29 by r111122223333

[GregValiant 1,112]

The "Gaps" thing.  This comes up occasionally on this forum and I tend to agree with other people on this that the root cause is a shrinkage issue that transcends the slicer being used.

 

This might not be what's going on in your specific case, but it is my take on the behavior.

If enough time passes between each curved wall extrusion being laid down then shrinkage will occur and the next perimeter doesn't connect to the previous one.  This is really hard to fix but making sure your filament is dry can go a long way.  If you have a very good layer cooling system and you are running it hard when these extrusions go down (particularly Inner Walls around a small hole) then that can make the condition worse.

 

Most filament comes in a sealed bag with a desiccant pack.  That guarantees nothing.  I've opened new rolls of filament and they were, well, not sopping wet, but pretty darn close.  That is not a popular problem, but it can certainly happen.

I have experienced the gap problem myself.  I started paying more attention and it usually occurs with rolls of filament that I've left out, or that have just sat on the shelf for too long.

 

I see you have an S5 so the "Flow" should be correct.  There are a couple of other things you can try without requiring that the slicer be re-written.

• Hole Horizontal Expansion - The smaller the diameter of a hole, the more likely that the "Snot Factor" will come into play.  That condition happens because the extrusion wants to get dragged in towards the center of the circle rather than stay on the periphery where it belongs.  The extrusion WANTS  to follow the nozzle and not form an arc.  The gap can occur because the inner wall extrusion isn't where it's supposed to be.  This is often why small holes don't come out at the design diameter.  I did a test and if the hole diameter is over about 30mm then the Snot Factor falls to zero and no HHE is required.
• Inner Wall Flow - By kicking this up you can force more squish which should tend to keep the inner walls where they belong.

Maybe you've thought of those before.  Because I haven't experienced the problem lately myself - maybe I'm just out of touch.  

 

 

 

 

[r111122223333 0]

This issue is not with an S5, that ws a machine I had use of a while ago, but mroe recently I've been using the Ultimaker forum just for general Cura advice. This is a CR20-Pro, UNENCLOSED unlike the S5 so susceptible to some amount of drafts, though I don't see shrinkage in other parts of the model.

 

Hole horizontal expansion is something I've used when printing precise shapes (like ring gears for planetary sets) as inner wall shapes, but I don't see any way it could prevent the shrinkage or "snot factor" on small holes from pulling the inner walls away from the infill. By what sort of amount are you suggesting multiplying flow, I'd already tried increasing the inner wall flow (does that only affect walls around inenr holes, or does it affect everything but the very-outer-most perimeter on outer nd inner perimeters??*), I'd been trying 120% with no improvement noticable.

 

Are there ways I can fix this to stop these gaps between inner facing walls and infill without causing over-extrusion on outer walls which would spoil the precision of outer side features.

 

Thanks

 

*there might be some problems with words here, not sure if there is a proper convention in 3d printing, or just within Cura, of how to describe the difference between whether a wall is "inner" (around a hole) or "outer" (around the external perimeter of a part) versus the wall lines which are very-outer-most/very-inner-most as in, respectively, walls which are visible in the final print as surfaces around the external perimeter/walls which are visible in the external print as surfaces around a hole.

Edited May 29 by r111122223333

[GregValiant 1,112]

Easy part first...

An outer wall is any wall with air on one side.  They are "red" in the Cura preview.  An inner wall has model on both sides and they are green in the Cura preview.  Anything that is part of a skin is "yellow" in the preview.  That would include any extra skin walls.

 

The "Extra Skin Wall" is the border around any skin area.  I was playing with the "Skin Overlap Percentage" and if there is a Skin Wall present it moves the Skin Wall closer to the inner wall (or if a negative number then farther from the inner wall).

 

What I noticed is that if the "Extra Skin Wall Count" is 0 then the "Skin Overlap Percentage" will act directly on the skins.  Setting the "Skin Overlap Percentage" to 50% (with the "Extra Skin Wall Count" = 0) might help.  It looks like it makes a difference in the preview, but there is no shrinkage in the preview.

This is with no skin wall and a Skin Overlap Percentage of -50% just to show what it does.  This sort of looks like what is going on with your prints.

 

But set to +50% you get this.  The Skin lines are mashed into the inner wall lines.

 

Maybe that has some value but you would need to do a couple of tests both with and without the Extra Skin Wall.