RE:
Hi. I want to throw something into this thread.
I have a similar issue with my Qidi Xmax3.
I printed a Simple model, a cylinder with a hole on its side. At the height of the hole, when perimeter loops are broken, a layer shifts. It is similar to your bulges, but…
My shift is not coherent. In yours, the bulges look uniform around the model.
I tried to print it on Bambu X1, Prusa Mk4, and Mini. They have better results, but it is there.
My model is a 30mm cylinder, but at the height of the hole, the offset layers have an ellipsoidal shape +-0.5mm
I notice, that there is a gap between perimeters at the height of the shift - top left, and bottom right. In these places, layers are shifted inside of the cylinder.
At the top right, and bottom left, layers are squished, and shifting outside of the cylinder.
Low speed, 30mm, improves quality. If I enable external perimeters first Then on the outside walls shifting is not so visible, but inside are no changes.
It looks better when I cut the model, and break the perimeters loop.
RE: Bulge when print reaches "solid" layers
I noticed this issue with one of my prints. I have a print with 3 mm holes and all of those lines that are connected to the holes are thicker, causing a bulged band throughout the print. It's even visible in the slicer preview. At first I thought it was cooling, and by adjusting the minimum layer time threshold I got the layers to have the same cooling, but I could still see the band in the preview.
Then I compared Arachne vs Classic, but comparing the line widths, the hole layers were still wider than the ones before or after the holes. Scrolling through the settings, trying to think what setting could affect these layers, I came across X-Y hole compensation. I'd set mine to 0.1 before for more accurate holes. I thought, surely it can't be that, but:
The difference between the line widths is 0.1, exactly what I've set my XY hole compensation to be. After setting that back to 0:
Both line widths after and at the holes are now the same thickness. You can also see that the band is now gone in the preview. I haven't tested it out yet because this an 8 hour print, but it looks like this could be at least one setting causing this issue. This was on Orca Slicer 2.0.0.
So idk, check yours and give it a go if you have a faster print to test with. I'll try it out tomorrow.
RE: Bulge when print reaches "solid" layers
Well I just had to test it today. XY Hole compensation seems to push the layers inward and cause a visible band. I printed 2 test pieces with otherwise identical settings, just with XY hole compensation set t0 0.1 on the other, 0 on the other. It is hard to get a good picture because the filament is white and my phone's camera sucks but here's the one with compensation on, with the bulging band clearly visible in the middle of the print:
And here is the one with no hole compensation:
The band is gone but there is still some inconsistency in the corner near the seam.
And here is the line width view from slicer, with compensation enabled on the right:
But PrusaSlicer doesn't seem to have this feature (I couldn't find it with the search, please tell me if it does so I can test), so there must be another reason why other people are getting these artifacts? It could be related to max and min cooling. If the range is too big (say <50 to 100%), there will be a considerate change in fan speed that could cause the layers to cool at different rates.