Strange lattice/stringing issue – does anyone know this failure pattern?
Hi everyone,
I’m running into a very strange print failure and I’m hoping someone here recognizes the pattern or knows the root cause.
I’m printing a lattice-style model and the outer perimeters seem mostly okay, but inside the structure I get massive random stringing/cross-connections between cells. It almost looks like the nozzle is “drawing” across open areas instead of following the intended paths.
The issue appears consistently on multiple parts in the same print job.
Printer/setup:
Printer: Core One+
Material: PETG
Nozzle: Prusa CORE One HF0.4mm
Layer height: 0.25mm balanced
Slicer: PrusaSlice 2.9.4
Firmware: 6.4.0 (downgrade from 6.5.3 because of failed filament sensor calibration)
Temps: 220°C for other layers (if I use higher temperature stringing occurs)
Filament: Geeetech 220 – 250 °C
What I already checked:
Filament is dry (or at least should be)
Bed adhesion is fine (used clue)
Belts are okay
No obvious clog
What confuses me:
The defect occurred after about 24 hours of printing
Has anyone seen a failure pattern like this before?Any ideas what could cause it?
Thanks in advance!
RE: Strange lattice/stringing issue – does anyone know this failure pattern?
You can turn on show travel in the prusaslicer preview to see what's happening. One thing you can try is turn on "avoid crossing perimeters" in print settings.
Formerly known on this forum as @fuchsr -- https://foxrun3d.com/
RE: Strange lattice/stringing issue – does anyone know this failure pattern?
if I might add.
You have that you have it at 220c for PETG, and that the filament is dry.
How do you know its dry? did you try drying it already? is it pretending to be the Snap Crackle and Pop spokes elves and making those sounds when it prints?
Did you try tuning / dialing in the filament a bit?
Are you getting the same result with other prints?
Check the model for any errors? (would have a little alert triangle next to the file name on the right side (if using prusa slicer)
Shane (AKA FromPrusa)
RE: Strange lattice/stringing issue – does anyone know this failure pattern?
Thank you very much for the responses 🙂 and additional questions👍:
@FoxRun3D: I will take a look at and test both settings. Thank you.
@Same-old-shane:
- I used a brand-new, freshly unpacked spool of filament. I also unpacked a second spool and it is running in parallel on a P2S printer. The results couldn't be more different (see image below).
- On the Core One+, there is indeed a sort of grinding noise occurring—which is not present on the other printer.
- I did experiment a bit with the filament settings (e.g., material flow). Perhaps not enough?
- Regarding the prints on the Core One+, I am encountering the exact same problem, though sometimes it happens sooner and sometimes later. This morning, the other two prints I had running were ruined as well (see images below). For two of the prints, the issue appeared early on, while for the other two, it occurred about 15 hours later.
- The model itself is fine—I have printed it multiple times already, particularly on my other printer. On the Prusa, it also printed successfully 2 or 3 times just a few weeks ago (using the same filament and settings —which, at that time, hadn't even been dried and wasn't fresh out of the package).
Additional question:
- I recently purchased an E3D ObXidian nozzle. Would swapping out the current nozzle for this one make any difference in this situation?
I ordered a dedicated filament dryer yesterday. As soon as it arrives (which should take a few days), I will definitely address this variable to rule out moist filament as the cause (though, as mentioned, it is working fine on the other printer).
Thank you again for your help!
The dessicant with a new filament keeps it dry for a few months but you don't know how long it's been on the vendor's shelf. Never assume new filament is dry.
Even if it did start dry, if you are in moist atmosphere PETG can absorb enough moisture during the printing time that the later layers are degraded.
You have a dryer on order, good. If that is not enough printing from a drybox might be necessary...
Cheerio,
RE: Strange lattice/stringing issue – does anyone know this failure pattern?
Couple of ideas for trouble shooting:
* Swap in the Obxidian nozzle. If it works, the other nozzle might be the culprit. I for one am not a fan of the HF nozzles, seen too many issues. I only use regular flow Obxidian.
* Try to print the model with the filament spool that worked fine on your P2S. If it prints fine, then the filament is the culprit.
As Diem said even new nozzles may be dry (even though I have rarely seen this happen). But I've also had just bad batches that would never work, even after extensive drying (again, rarely).
Formerly known on this forum as @fuchsr -- https://foxrun3d.com/
RE:
- I used a brand-new, freshly unpacked spool of filament. I also unpacked a second spool and it is running in parallel on a P2S printer. The results couldn't be more different (see image below).
It's a common mistake to assume a freshly unpacked spool is immediately printable. It's possible the second spool was packed under better conditions or didn't sit around as long as the first spool. Unless it's PLA, I always put the filament in a dryer before a print.
If you swap the filament rolls between the two printers are the results the same? If so then perhaps that rules out the filament as the cause.
Anyway, different printers, different nozzles, different slicers.
What I'm seeing on the Core One side is possibly a retraction issues as well as perhaps a partial clog. Are you seeing similar issues with the same filament but different geometries? As a test, try printing just a single cylinder.
Also, does this happen as well with other prints? It could be an extrusion problem. Perhaps check the idler tension.
RE: Strange lattice/stringing issue – does anyone know this failure pattern?
The Core One shouldn't be making grinding noises. I'd take a look at that and see if there's binding or some problem. I'd particularly look at Z but look at everything! The print in the photo looks bad right from the start; the first 1/2 inch is in trouble. No need to continue when there's obviously a problem.
RE: Strange lattice/stringing issue – does anyone know this failure pattern?
@markus-reichert
You got several different things to check, I would suggest to try them one at a time, make a note of the results and then update the post, YES, I know it sounds stupid to say that, but also posting it so the thread doesn't have 20 different things and becomes overwhelming 🙂
Shane (AKA FromPrusa)
RE: Strange lattice/stringing issue – does anyone know this failure pattern?
Dear all,
thank you so much for all your support, ideas and hints.
In summary I will do:
- swap the nozzels (using the Obxidian nozzle)
- dry the current spool (as soon as the dryer arrived)
- try the current spool which is working with the P2S- I will also open a new spool
- I started to build a filament box / drybox with a connection to the printer (missing parts already ordered)
- I will check a possible retraction issue and a partial clog issue
- I will check the idler tension / extrusion problem
- Test print: a single cylinder- Comparing with other test prints / geometries
- I will check possible binding problems
Because of the delivery of several orders/parts I will need several days to check all the points/proposals you mentioned.
As @same-old-shane proposed: I will come back in a few days and will update the summary list above with the dedicated results.
Thank you again!