Wall bulge

[MBPrints]

Hi everyone, starting to love this forum as my problems get solved. I’ve got another problem which is wall bulging. I have a visible wall bulge on the outside wall at the same layer where there is a top surface infill on the other side of the wall I’ve attached photos below. Any ideas what settings may be causing this, I’ve tried changing wall perimeters and that’s it really, any help would be great. Thanks Matt 

[Nurgelrot]

Does it coincide with the top fill on the inside of the part? If so it could be caused by your solid infill or top layer overlap %. Sometimes a simple fix its to just print exterior perimeters first. So the over pressure pushes "in" rather than "out". Doesn't work on all prints though.

Edited March 11 by Nurgelrot

[MBPrints]

13 minutes ago, Nurgelrot said:

Does it coincide with the top fill on the inside of the part? If so it could be caused by your solid infill or top layer overlap %. Sometimes a simple fix its to just print exterior perimeters first. So the over pressure pushes "in" rather than "out". Doesn't work on all prints though.

Hi Nurgelrot,

It does coincide with the top fill on the inside part, Unfortunately I need it to print inner walls first due to free standing overhangs, however I haven't tried reducing the infill overlap %, I'll give that a go thanks. 

 

[GarthSnyder]

I see this occasionally, in exactly the circumstances you describe: the print goes from a solidly-filled layer to walls only. I don't know what causes it, but I've been running some experiments.

I initially thought this might be an artifact related to extrusion multiplier, on the theory that slight overextrusion might push out the wall of the solid region a bit. But experimentation didn't bear this out. In fact, I was able to get a slightly less prominent bulge by raising the extrusion multiplier. ¯\_(ツ)_/¯ 

Two other factors that I believe are not related to this problem are speed/acceleration of perimeters and overlap percentage between perimeters and fill. (I'm using PrusaSlicer, if that makes any difference.)

Outer Perimeters First does help, but my goal is more to understand what's going wrong.

[Kaye7877]

I have the exact same problem I am chasing with prints I do in ABS.  Seems that the problem also exists on the other parts printed at the same time.  In the recent past, I think I saw a prominent YouTuber video on this problem but I can find it. Will look today. 

[DanPin]

In general, how can this be a problem with print settings since there are two square extrusions, and only one seems to be bulging.

I would have expected both to show the same problem.

Or am I not seeing something in the photo?

[MBPrints]

9 hours ago, Kaye7877 said:

I have the exact same problem I am chasing with prints I do in ABS.  Seems that the problem also exists on the other parts printed at the same time.  In the recent past, I think I saw a prominent YouTuber video on this problem but I can find it. Will look today. 

Hi Kaye, that would be great thanks 

[MBPrints]

6 hours ago, DanPin said:

In general, how can this be a problem with print settings since there are two square extrusions, and only one seems to be bulging.

I would have expected both to show the same problem.

Or am I not seeing something in the photo?

The photo doesn’t really show but it happens on both parts 

[DanPin]

1 hour ago, MBPrints said:

The photo doesn’t really show but it happens on both parts 

Copy...Thanks....now I waiting to hear the fix....

[c1ph3r]

I had these same issues when I first started printing with ABS. I assume it’s the same regardless of material. It’s not actually a budge but rather shrinking from surrounding areas that give the impression that one area is bulging . I fixed it by doing a lot of trial and error with cooling. But here’s an article from Prusa that explains more of it. 
https://help.prusa3d.com/article/the-benchy-hull-line_124745

 

Edited April 3 by c1ph3r

[MBPrints]

On 4/3/2024 at 11:12 PM, c1ph3r said:

I had these same issues when I first started printing with ABS. I assume it’s the same regardless of material. It’s not actually a budge but rather shrinking from surrounding areas that give the impression that one area is bulging . I fixed it by doing a lot of trial and error with cooling. But here’s an article from Prusa that explains more of it. 
https://help.prusa3d.com/article/the-benchy-hull-line_124745

Hi there, sorry for the delayed response, like you said I tried alot of trial an error and looked into this link you attached with no success. What specific settings helped you ?

[c1ph3r]

Looking back on it, it was fan speed and the layer the fan comes on. I use a constant fan speed from layer 2 on. No fan on layer one. And the fans speed isn’t that high. Like 25% I think. This is on a Qidi XSmart3 by the way. I do still have the problem on occasion in parts of a part depending on how the fan does blow on it. But it seems to only do it on overhangs that are in an odd spot in relation to the fan.

[mvdveer]

May be worth playing around with the overhang settings in the Filament TAB:

 

[MBPrints]

13 hours ago, c1ph3r said:

Looking back on it, it was fan speed and the layer the fan comes on. I use a constant fan speed from layer 2 on. No fan on layer one. And the fans speed isn’t that high. Like 25% I think. This is on a Qidi XSmart3 by the way. I do still have the problem on occasion in parts of a part depending on how the fan does blow on it. But it seems to only do it on overhangs that are in an odd spot in relation to the fan.

Okay thanks for the advice I’ll give a constant fan on a go

[MBPrints]

1 hour ago, mvdveer said:

May be worth playing around with the overhang settings in the Filament TAB:

I have played with these but I’ll give it another go