Outer Wall Layer Line - Puzzling

[TinkerP29]

Hi All,

I am experiencing a puzzling issue with a print from my P1S. This was a once reliable print, but the printer has started adding a “band” “line” around the part where there is a partial solid infill. This was printing fine with no outer line. I did not change any slicer settings, which makes me think it is a mechanical problem. Though it could also be a software update issue, I suppose. I would appreciate any troubleshooting ideas or tips. Here is the history.

I have a working BambuSlicer Profile I have printed many times before. The original profile uses a 0.6mm Hardened Steel nozzle with Bambu PETG-CF. It’s had nice smooth walls with no issues. I haven’t printed the profile in a month, and now when I print there is a visible line around the print.

You can see in the picture the line coincides with the start of the solid infill of the top surface of the triangular hole. My attempts to resolve this so far:

1. Tried a 0.4mm Hardened Steel High Flow Nozzle
2. Tried a 0.6mm Hardened Steel Nozzle (Original from print file)
3. Dried out the PETG-CF and printed again
4. Switched dried Creality PETG filament
5. Tightened the x-y belts, cleaned the carbon rods, and recalibrated the P1S
6. Altered BambuSlicer Settings:
   1. Changed from Arachnae to Standard wall creator
   2. Changed infill overlap from 15% to 10% to 8%
   3. Slowed down the print speed

What is so strange is that the profile worked flawlessly before. So changing thee Slicer Settings doesn’t seem to be the issue. To me, it points to mechanical. But tuning the machine, changing nozzles, and changing filaments doesn’t help. What else should I look at?

Thanks so much!

Holder.v4_plate_1.gcode.3mf (572.2 KB)

[Holzfuss]

Your printer is perfectly fine. The bridge layers beginning over the infill and the layers of the inner massive infill took longer than the rest of the layers. You can try up the speed of the bridge and if you wanna tweak more youd probably have to disable the fans for this print

[TinkerP29]

Thank you for your thoughts on how to fix this. I am confused why this went from printing with no line to printing with a line. I didn’t change anything in the slicer.

I see the layer speed you are referring to. It does coincide with the line in the outer wall. I tried to increase the Bridge Speed and Gap Speed to 1000 mm/s each, but I still get the same layer speed. What else would be controlling this?

I attached the model file. Thank you again.

Holder Part.v4.3mf (2.6 MB)

[MZip]

@TinkerP29

I didn’t change anything in the slicer.

But Bambu may have. You may need to experiment a bit to get it back proper again.

[TinkerP29]

Well this is odd. I can’t seem to change the bridging speed in BambuSlicer. Here is the original. You can see the printer slows way down to cover the infill.

When I change the speeds for Overhangs, Bridge and Gap, nothing changes with the speed.

[TinkerP29]

For anyone who is runnning into this or something similar, I was able to resolve the problem. I performed a full clean on the nozzle and I also cleaned up the Z-axis lead screws. I performed a belt tension just in case. But I think it was a dirty nozzle in the end.

I followed the steps in here for unclogging and then checked I wasn’t dealing with cracking. If you are swapping filaments, try increasing the purge time between them.

Model interlayer cracking

Then to check the Z-Axis: Solutions for Z-axis screw rods looseness and Z sliders misalignment | Bambu Lab Wiki

I hope this helps!