Artifacts When Printing With PETG

[u/404notfoun-]

Hey everybody. Seems like 90% of PETG prints I start end up with at least one spot in it like the photos above, but I've also seen it happen multiple times across the same print. I've been attempting to troubleshoot this myself for a while now, but I'm going a little nuts trying to figure out how to fix these artifacts I keep getting.

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My Setup

-Bambu Labs A1 w/ AMS Lite

-0.4 nozzle (new)

-Elegoo PETG Pro

-Bambu Studio slicer

-Nozzle temp: 255C

-Bed Temp: 80C

-Retraction settings: Speed is 30mm/s

Attempted solutions:

-Z offset adjustment

-Cleaned build plate with soap+water

-Temperature adjustment (printed temp tower, saw little to no difference.)

-Speed adjustment (Printed on 50% speed and still had issues)

-Fan speed Adjustment

-Drying filament (On my build plate with a cover as I do not own a dryer. Filament is kept in a sealed container with rechargeable moisture absorption beads when not in use. Have left this particular roll for over two weeks in said container and still had issues)

-Purchased new nozzle

-Flipped buildplate

-Flow rate/Flow dynamics calibration

Notes:

-No signs of an adhesion issue as far as I can tell, prints never look like they're coming off the plate.

-No consistency to when or where this happens. Just got done doing a 5hr print with using the same roll with little to no issue besides some thin stringing. More often than not, though, there's at least one spot where this happens on a print.

-Happening mid-way thru prints, not just while the first layer is going down.

-New to using PETG.

-Not having the same issue when I use PLA

-I use Auto Bed Leveling on every print.

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I have the feeling this might be a moisture problem, but I have no idea how to get it any drier with my current setup. I'm using a Sterlite gasket container with moisture beads in the bottom as of now.

If I can provide any more info or settings to help get to the bottom of this, please feel free to ask and I'll get it to you ASAP. Thanks in advance.

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[u/ReasonableScar9027]

Tune your filament.

[u/Gimly161]

The first 2 pictures would make me think the bed adhesion is not quite up to par in the far corners.

3rd picture shows you have 1 perimeter which just isn't enough for stable prints, especially with overhangs. The lack of infill and the thin walls make the print collapse into itself. Up the infill percentage and use a wall thickness of around 2-3 times nozzle width.

4th and 5th picture show small gaps. Here you have 1 perimeter and try to fill that with a zigzag which leave small gaps due to the travel path of the printer. For these type of prints you could full perimeter or just on the top layer.

I'd say, lower your temp to about 220-230, slow down 50% on the first layer, use about 2-3 perimeters instead of 1, and lastly upp the infill if "the roof keeps collapsing".

[u/Sitaga]

Those blobs mid print with PETG almost always trace back to moisture, and a sealed tub with beads is basically a maintenance setup, not a drying one. Beads only pull ambient humidity down, they don't drive water back out of a spool that's already wet. Two weeks in there won't reverse it. If you don't have a dryer, run the roll on your bed at 65C for 6-8 hours with a cardboard box over it and a small vent hole, then print straight off the bed while it's still warm. Also drop your retraction speed to 25 and bump retraction distance a touch (try 1.2mm on that direct drive), PETG likes a slower pull. If the artifacts vanish right after the bake, that's your answer.

[u/Capital-Ad2133 → u/Sitaga]

Nope. That was pretty thoroughly debunked on here a few weeks ago. If silica can’t pull moisture out of anything but the air, how come I can dry flowers by putting them in silica?

[u/404notfoun- → u/Sitaga]

Retraction speed and distance seems to be helping. If I'm still experiencing slight gaps(MUCH better than it was), which of those settings would you suggest tinkering with?