I’m using Creality Hyper PETG with the profile of Bambu PETG-HF and limited the volumetric speed to 12mm3/s.
However I have a problem with the wiping procedure tearing apart the layer lines.
I think the problem has to do with cooling or layer time, is that the right approach?
Explain what you mean by that.
Are you trying to clean up a seam by changing the volumetric speed?
Try using the Scarf options in the filament settings.
Also, use the seam toggle (click the line entry) to see them in the preview.
Read my recent answer with more details on this feature, and it will help you understand the cause.
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If you look carefully in the picture you will see that the seams are fine. What is not okay is that after the seam the layer lines have peeled or ripped off by the nozzle. When I looked in the slicer I could see that the printing was from right to left. So the conclusion I’ve come to is that during the wiping action the lines are getting ripped off by the nozzle.
I am wondering, if you switch to Scarfs does the problem go away?
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With PETG Basic, I had similar issues when it came out.
Turned out
- the profiles were bad (cooling from Generic PETG was much better),
- it really does need to be dried,
- and “wipe on retract” in the filament settings can help.
- Not sure if a Pressure Advance calibration will help as I do not have an A-series.
Also, I have found PETG to reward going slower. The slicer preview will tell you if (that part of) your print is mainly flow or speed limited.
I also like the scarf seam option as recommended by @MalcTheOracle . I tend to go for the full circumferential option most of the time.
It still happens even with Generic PETG cooling parameters.
Regarding your other points. The filament is dry, the Pressure Advance is calibrated manually to 0.04.
Did that use “wipe on retract”?
I have found that to be quite important with PETG.
Then, there may be further troubleshooting neccessary. Do you only have these defects on inside perimeters? It may be worth slowing down in that case. PETG usually rewards slowing down.
Not sure about that big “string” at the end though. That is rather puzzling as there should have been a retract before finishing the print…
I did another test, I disabled Wipe on Restract and still the same. So it’s not the wipe action that is doing this…
I need to think what’s causing this.
Ok, that is strange.
I have found timelapses and of course direct observation quite useful when troubleshooting. As is of course posting the model and full settings here.
I would hope that scarf seam could aid, but the failure pics indicate a more fundamental issue (to me). PA, wipe, retract, z-hop, (advertised) speeds/accelerations, settings promoting nozzle sticking,…
If the printing is from right to left, and the pic is not upside down, then I would suggest that you look into your travel and retraction settings. It looks like there isn’t enough material/hardened material in/on the nozzle on the LEFT of the seam, aka when it starts printing the line. Ooze loss?
When you took this off the plate, was it full of wispy crud? That could be your “missing material.” aka ooze control
Follow PETG anti-ooze recommendations aggressively and see if it helps. (travel speed/accel/jerk UP, retraction test this filament, print speed slower, arrange models so there isn’t a long travel between them, etc)
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I think you are on to something.
Yes, the print is from right to left.
I’ve tried to reduce the retraction length to 0.4 from 0.8. And Z-hop was reduced to 0.2 from 0.4. But it’s still the same.
There is ZERO oozing or webbings.
I have slept on this overnight, I think that yes, as you’ve said there is not enough material or hardened material in the nozzle.
But why? I can only speculate, it may be because of the too fast acceleration that makes the hotend separate the nozzle contact, not letting it transfer the heat properly.
Does it make sense? I dunno.
Where is the PETG anti-ooze guide? I would like to read it
Found a solution, changing Wall Generator from Classic to Arachne solved the issue.
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It’s definitely not the reason of this issue. Have you tuned your filament’s PA?
Yeah, you are right. It’s not the reason. Changing the Wall Generator from Classic to Arachne made the exterior of the model less beautiful. Yes PA has been calibrated, it’s 0.04
I’ve found the culprit with the help of this video:
The nozzle pressure is dropping due to the slicer printing lines with small line width to fill gaps.
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