Bulge when print reaches "solid" layers  

RE: Bulge when print reaches "solid" layers

I'm facing this issue and let me chime in and add some observation.  While I was following my print, the bulge starts appearing during the last layer of the top infill.  Using SuperSlicer, I can see that when guilding that layer, a gap fill is added (which is fine).  Now, check the width of that gap fill where the issue starts:

If we compare it to the gap fill of the next layer (first layer with perimeters only), this gap fill is reduced to give room to the inner outside perimeter.

Plus, we can see that during the print of the faulty layer, the gap fill is printed last:

Could it be that this gap fill is pushins outside perimeters and produce that bulge?  That gap fill is wider, so when it prints, it puts pressure on outside walls.

Could it be related to the issue?

RE: Bulge when print reaches "solid" layers

I am plagued with this issue in Cura mostly, so when I had a smaller piece that had a severe layer bulge, I deceided to do a bit of testing. I first printed the part in Cura, PrusaSlicer & Superslicer.  Of theese Cura was worst and Prusaslicer with barely any issues, making it the best. I then tested printing the parts via Octoprint and via SD, but experienced no change there. I then reprinted the cura one, and keept an eye on it when it reached the part where the bulge ocured, and it was indeed creating som offset relative t0 the rest of the print.

I then on a whim deceided to try the Cura Arachne beta, using the same settings as the normal one, and the issue was greatly reduced.

Spurred on, I created a "tetris" block in the shape of an "L", expecting to see a line where the transistion happened. but it was smooth with no defects.

Now, I am no expert, but to mee it semmed like the Slicer deceided to give the top layers some extra squish, and this carrying over to the rest of the print (it was in two parts on the buildplate, and visible even the part without the "shelf" at the same heights.

Included pictures is Cura on the Left, PS on the right. 

I am not sure what to make of this, but if any of this info can help anyone I figured I might as well post it. 

All parts printed on a CR-10s Pro V2.

RE: Bulge when print reaches "solid" layers

The bulge is a struggle.  I have not noticed it in PS 2.4.  It might be there.  I will try to reproduce it.  

RE: Bulge when print reaches "solid" layers

Yeah, it is annoying the crap out of me. I have it on two Creality printers in Cura, so it seems like it is printer/slicer agnostic to some extent.  I cant for the life of me figure out why it treats that part of the wall  as a top layer. Atleast this forum seems open to figure it out, most places I am met with "clean your Z-rod", swap your wheels, etc.

RE: Bulge when print reaches "solid" layers

After a bit more research, slicer swapping and theorycrafting I found a way to mitigate it greatly on my machine. I took a functional print I had, with bad bulges, measured with Calipers, and found the pieces were a bit smaller than they should be, exept for the bulge, that was spot on. This spoke to me about a bit of underextrusion in general on the part, but I had calibrated my E-steps/flow not long before.  Testing the same piece in a different slicer gave me VERY sligh underextrusion.  Redid E-steps, came to same number as before.. 

Changed Bowden tube, no visible change.

Deceided to up  e-steps by .5 and presto, much better.

I am suspecting volumetric issues.

RE: Bulge when print reaches "solid" layers

Oldie but good here.  I just pulled up a .3mf I hadn't printed in almost exactly a year and resliced with 2.3.3.  This is still present lol.  Both my printers are going right now but tomorrow I might try to slice with 2.4 as built from master this morning and see if anything changed.

RE: Bulge when print reaches "solid" layers

Well, I can tell you -- no.

RE: Bulge when print reaches "solid" layers

Posted by: @fuchsr

Well, I can tell you -- no.

Bummer.  Thanks for the heads up!

RE: Bulge when print reaches "solid" layers

does anyone know if there's an open issue for this on the PrusaSlicer github ?

RE: Bulge when print reaches "solid" layers

The issue is mentioned here:

https://github.com/prusa3d/PrusaSlicer/issues/4355

I put a link to this thread in a comment on that issue.  I might open a separate issue just to it gets some developer eyes.

RE: Bulge when print reaches "solid" layers

I just opened this issue on github

https://github.com/prusa3d/PrusaSlicer/issues/7339

RE: Bulge when print reaches "solid" layers

so as to confirm what @fuchsr said, sliced with freshly built 2.4, the issue persists.
I'm hoping now that there's a ticket open for it on github it will get some developer attention.

RE: Bulge when print reaches "solid" layers

There is an issue open on Github.  I tried opening a ticket for this issue a while back and it was closed due to existing issue on it.

RE: Bulge when print reaches "solid" layers

hmm, I did some searches in both open and closed, but didn't see any.  oh well.  if they close mine they'll give me the number of the one that is currently open.

@ssill2

Do you understand why the issue was closed?

Regards

Swiss_Cheese

RE: Bulge when print reaches "solid" layers

not really no.  This isn't an esoteric use case that I feel should require a bunch of tweaking to eliminate.  It's a pretty basic use case that I feel the slicer could easily notice and handle.  Heck, if I import one of the key chains I create it recommends the where to position the color changes....  

Posted by: @swiss_cheese

@ssill2

 

Do you understand why the issue was closed?

 

Regards

 

Swiss_Cheese

RE: Bulge when print reaches "solid" layers

Alright they responded back with a helpful comment.  

"
Similar to #991, #1719, #3423, #4010, etc.

See this comment for further information #991 (comment). It is very difficult to compensate for all the influences mentioned there, but improvements related to this topic are on our todo list.
"

RE: Bulge when print reaches "solid" layers

It is still there

RE: Bulge when print reaches "solid" layers

Try this one: https://www.prusaprinters.org/prints/123334-thrustmaster-tflight-hotas-one-throttle-fix. Action starts to happen when the interior starts sloping inwards, and theres a bulge on the outside. 

RE: Bulge when print reaches "solid" layers

I've been slowly switching over to PrusaSlicer after waiting years for Simplify3D to come out with an update.  I recently ran into the "bulge" problem, and didn't realize this was a long standing issue.   I posted a new thread here: https://forum.prusa3d.com/forum/prusaslicer/exterior-bulge-corresponding-to-internal-cavity/#post-579034

I'll add a note directing folks to this thread. 

I can add a few comments, although given all the work done in the previous 22 pages, I'm not sure how much it will help:

1. The bulge on my print is BIG.  I measured 0.28 mm, when my extrusion width is 0.40 mm (carefully calibrated for this spool of filament).
2. It's directional.  The model I'm printing is basically a rectangular bar, and the bulge is non-existent on one end, and very pronounced on the other end.   One side is OK, and there is a slightly smaller bulge on the opposite side.  
3. The problem goes away when I print in Simplify3D.  Others have reported success in eliminating the bulge by switching to Cura or SuperSlicer.
4. In my case, the bulge occurs when the model switches from a thick bottom with infill to a wide exterior wall.
5. I'm printing on a MakerGear M2E, so it's not just a Prusa printer problem.
6. I'm using PrusaSlicer 2.40, so it hasn't been fixed in the latest version.

Here are some pictures:

This thread: https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-how-do-i-print-this-printing-help/any-tips-to-get-rid-of-the-bulge/

suggests that you may be able to get some improvement by setting:

1. Gapfill = on
2. Thin walls = on
3. Overlapping perimeters =off

I haven't had time to check if this helps with my print.