bad overhangs especially on thin pieces
Hello everyone,
I’m hoping someone can point me in the right direction because I’ve been fighting this issue for about six months now and I’m honestly pulling my hair out.
Basically, I’m getting really bad curling on overhangs. It’s happening on pretty much everything, but it’s super obvious on functional parts like fan ducts. The edges curl up hard, which ends up ruining the surface finish and distorting the geometry.
Here is the weird part: it’s happening across the board, regardless of the material.
ABS: eSUN and Generic (Purple parts in my pics)
PETG: Prusament (White part)
PLA: PolyTerra and Sunlu
I’m using stock PrusaSlicer profiles for everything. I know orientation plays a role, but even on "safe", so everything above like 25°, angles, the curling is way worse than it should be. Especially since i had extremely nice overhangs for the first few 80 hours.
My setup & what I’ve tried: I'm running a Core One with the latest hardware and a CHT brass nozzle.
At first, I thought it might be a partial clog, so I did a cold pull. I got all 3 strands from the CHT nozzle cleanly, so the nozzle seems fine. Since it’s happening with PLA, PETG, and ABS (which all have different cooling needs), I feel like I’m missing something systemic.
Has anyone else seen this kind of behavior on the Core One? I'm wondering if maybe the stock profiles don't play nice with the CHT nozzle flow, or if there is something up with my fan/duct airflow?
Any ideas on what to check next would be a lifesaver. I feel like I've tried all the obvious stuff.
Thanks in advance!
RE: bad overhangs especially on thin pieces
Since you mention a long (six months) time span: Do you dry your filaments before printing?
RE:
didnt do it originally but now i do, i did ~7 hrs on a creality dryer with the right profile.
it didnt change anything though 🙁
RE: bad overhangs especially on thin pieces
Have you tried orienting the critical overhangs towards the back of the printer? (Assuming the problematic overhangs occur mainly in one direction in your part.) The fan duct on the Nextruder does not guarantee fully symmetric "360°" airflow towards the printed part. In the Mk4 cooling was better on the front, in the Core One it seems to be a bit better in the back, presumably due to more direct air flow from the part cooling fan.
RE: bad overhangs especially on thin pieces
yep, i tried that aswell.
i just dont know why it would happen after printing for some time and not from the beginning.
i did a print when it was still okay, so ill print the exact same gcode later and send comparison pictures.
why it would happen after printing for some time and not from the beginning.
This is sometimes a clue - We often see seasonal changes in reported problems when either the ambient temperature and humidity change naturally or, slightly less obvious, AC and central heating are switched. This is particularly common with unenclosed printers but the core one is not completely immune to what happens outside the case.
Thin overhangs have little resistance to bending and, especially when curved, the thermal contraction as the perimeters cool causes a slight bend which builds up with each layer. The cooling and consequent contraction are affected by ambient temperature, hence seasonal differences.
If the overhang is not too extreme it can sometimes help to set 'External perimeters first' - you will need to be in expert mode. - but, of course, on extreme overhangs this will fail as there is nothing to support the extrusion...
And it almost always helps to slow down problem prints.
Cheerio,