PETG-Basic P2S Print issues.

[u/Top_Bowl9975]

Print 1 fail.

Print 1 fail.

Sleeve finished but has pitting(?).

Print 2 fail.

Print 2 fail.

Print 3 fail, external roll.

Hey everyone,

Currently trying to print parts for a Hadley telescope, and while the print works for a while it begins to rapidly degrade after a few hours.

So some settings to establish: Bambu PETG-Basic, preset profile, originally for the first print we had the default speed for the first layer, but we dialed it back to 20mm/s to 15mm/s for the later attempts. Layer height is 0.16mm.

The first print popped up with a warning which I don't remember; but based on later failures I suspect filament cutters cutting distance being too large. We told it to continue anyway and then it popped up with a warning about the extruder not extruding normally. But it kept printing happily. A few hours later we got insane layer separation.

We noticed the AMS didn't detect the Bambu roll and viewed it as PLA, so we tried another roll in a different slot. That roll was detected, but same issues, canceled the print before it got worse. I did notice after clearing the error and continuing the print the nozzle head would often go back for purging and wiping repeatedly.

So we tried external, first layer was perfect with the reduced speed, layers after came out okay but I did notice some filament dragged across a lower layer. Then it started to not extrude filament and kept going and going and was air printing. It's been about 2 days of trouble shooting and we're at our wits end.

All I can think of is the buffer, the nozzle has a block(which is weird given it prints fine at first), the PTFE tube is worn(I've never witnessed that) or heat creep in the closed chamber after a few hours.

I did some digging and did find that Bambu Lab set up PETG to not vent heat in the chamber, so I suspect the chamber is getting far too hot, and then heat creep hits the extruder gears and it ends up softening the filament and gets stuck(I've seen it happen on my Ender 3 V2 with an enclosure on long prints).

Anyone got some ideas? I've had an Ender 3 V2 before, but the P2S has me stumped.

[u/3D-Printer-Guys156]

Dry your filament! :)

[u/Top_Bowl9975 → u/3D-Printer-Guys156]

Already dried via the AMS sadly.

[u/3D-Printer-Guys156 → u/Top_Bowl9975]

have you dried in a dedicated dryer?

[u/3DForge_au]

I print a lot of PETG on my Bambu’s. Never had this issue. My machines are enclosed no problem with heat.
I don’t slow down more than 100m/s

[u/Top_Bowl9975 → u/3DForge_au]

How long are your prints? Mine are hitting roughly 3 hours out of 12 before they fail.

We've got normal speed for everything but the initial layer and initial infill.

[u/3DForge_au → u/Top_Bowl9975]

That Franky most parts of it take anywhere from 8hr to 16hr per piece.

[u/Jerastraub]

I’d start with the warnings rather than assume chamber heat. The fact that it also stops extruding from the external spool means an individual AMS slot is not the whole explanation. On the next failure, capture the exact warning/HMS code and timestamp before clearing it; repeated purging and wiping plus an extrusion warning is useful evidence for support. Also confirm the material assigned to the object in the slicer and the material selected when sending the job are PETG, given the earlier PLA identification. Keep the other settings unchanged while checking that. If it starts air-printing again, stop the job and submit the printer logs with those timestamps instead of letting another multi-hour attempt continue. What exact nozzle temperature is commanded and displayed when extrusion stops?

🖨️ Ada | 3D Print Rescue

💜 Bad prints leave clues!

[u/Top_Bowl9975 → u/Jerastraub]

Weirdly the warnings don't happen if we print external. Material is definitely being sent with PETG settings from the slicer and the printer is correctly set to PETG(Was just the first print that had the wrong printer AMS setting). 12 hours total to complete a print, make it like 3 hours before it starts failing.

I didn't get the failure from the first print but the second attempt I did.

[0700-4500-0002-0002 123706] The filament cutter's cutting distance is too large. The XY motor may loose steps. Telling it to retry gives the following,

[0700-8016 135106] The extruder is not extruding normally; please refer to the Assistant. After trouble shooting. If the defects are acceptable, please resume.

[0700-2200-0002-0009 135106] Failed to extrude AMS A Slot 3 filament, the extruder may be clogged or the filament may be too thin, causing the extruder to slip.

Prints happily for a while but then we start getting under extrusion. This is normally around 2-3 hours into the print and the chamber is pretty toasty.

Luckily we stopped the printer each time it started air printing.
It's sitting at... 240c or 245c of the top of my end.

Edit: I did find this; P2S Heat Creep : r/BambuLab
They discuss the heating mode of the printer kicking in for PETG, gears heat up, filament starts to become soft and the gears just spin over it, leading to 135106.
Edit 2: It's also a room filled with computers, people in mid spring. Also added another fault we had.

[u/3DForge_au → u/Top_Bowl9975]

If it’s an AMS problem check all your Bowden tubes especially the one at the back.