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Terrible PETG infill  

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Anisotoph
(@anisotoph)
Eminent Member
Terrible PETG infill

My XL just won't do PETG infill nicely. The walls and top/bottom layer look fine, but the infill looks like the extrusion is sputtering. I've cleaned the nozzle and tried adjusting temperature, with no success.

The same slicer will generate beautiful output on my Mk4S with PETG, and the XL does great with PLA. I'm at a loss.

Posted : 15/01/2025 4:36 pm
FoxRun3D
(@foxrun3d)
Famed Member
RE: Terrible PETG infill

Looks like Grid infill. I'd try something else such as Cubic or Gyroid. Surprised it works on your Mk4S.. Grid is just horrible as it build up filament at the intersection that eventually trip up the nozzle. 

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Posted : 15/01/2025 10:23 pm
Brian
(@brian-12)
Honorable Member
RE: Terrible PETG infill

Also looks like underextrusion.  I see you said you played with temperature, but what temperature are you printing at? 

What filament brand are you using?

Are you using an enclosure?

Posted : 15/01/2025 10:56 pm
Anisotoph
(@anisotoph)
Eminent Member
Topic starter answered:
RE:

I ran some tests on different infill and got the attached. Clockwise from upper left:?(I don't think I noted this one correctly, so not sure), gyroid, cubic, grid. Gyroid definitely looks a lot better.

I also ran an extrusion calibration cube and got 0.445. So only 1% off. That doesn't seem to be enough to explain this.

Polymaker filament, no enclosure. Again, grid works perfect on the Mk4s that sits one shelf down from the XL. Very odd.

This post was modified 3 weeks ago by Anisotoph
Posted : 18/01/2025 4:30 pm
Brian
(@brian-12)
Honorable Member
RE:

You need to run polymaker hot 250c and 240 for the first layer.

Can you upload a 3mf so I can see your settings?

Posted : 18/01/2025 4:33 pm
FoxRun3D
(@foxrun3d)
Famed Member
RE: Terrible PETG infill

There's more going on than infill. Yes, gyroid looks good but cubic should be fine too. So I'm inclined to agree with Brian to see what happens if you run it hotter, even though in my hands polymaker has worked fine at generic PETG settings.

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Posted : 18/01/2025 4:40 pm
Anisotoph
(@anisotoph)
Eminent Member
Topic starter answered:
RE:

Tried 240/250 and it didn't change much; I was able to confirm that the top left in both runs was 3D honeycomb. The 3mf file is also attached.

 

 

Posted : 18/01/2025 5:14 pm
Anisotoph
(@anisotoph)
Eminent Member
Topic starter answered:
RE: Terrible PETG infill

Argh 3mf attached this time. The forum doesn't seem to want me to attach more than one file at a time.

Posted : 18/01/2025 5:15 pm
Brian
(@brian-12)
Honorable Member
RE: Terrible PETG infill

 

Posted by: @anisotoph

Tried 240/250 and it didn't change much; I was able to confirm that the top left in both runs was 3D honeycomb. The 3mf file is also attached.

 

 

You have to zip the 3mf and then attach it 

Posted : 18/01/2025 5:15 pm
Anisotoph
(@anisotoph)
Eminent Member
Topic starter answered:
RE: Terrible PETG infill

Ah thanks.

Posted : 18/01/2025 6:42 pm
Brian
(@brian-12)
Honorable Member
RE: Terrible PETG infill

I'm not seeing much, out of place.

I see there's some modified end g'code on the printer profile, not sure what it's for, but I'd return it to the standard profile. ( I don't suspect this is related to the issue)

I will say that I really struggled with the Polymaker PETG.  I normally use Hatchbox and I bought some rolls of Polymaker because the bulk price was good, but it was very problematic for me.  I would run the same gcode files that I ran with the Hatchbox PETG and I would get failed prints. After doing research I found that the maximum recommended printing speed for Polymaker PETG was only 50mm/sec vs. 100mm/sec with the Hatchbox.  What ended up working for me was slowing down the infill speed along with raising the nozzle temperature. 

I'd recommend to lower your infill speed and solid infill speed to 80mm/sec in the print settings tab under speed.

An alternative option would be to lower the max volumetric speed under the filaments tab and advanced.  If you were to lower that value to 7mm^3/s  that would do the same thing.

Please do one of the suggestions above and let us know the result.

Posted : 18/01/2025 8:42 pm
Anisotoph
(@anisotoph)
Eminent Member
Topic starter answered:
RE: Terrible PETG infill

Tried lower speed, marginal improvement. Then I realized I had a tiny bit of hatchbox filament left and ran that with the same slice. Not much change. 

Posted : 18/01/2025 10:50 pm
Brian
(@brian-12)
Honorable Member
RE: Terrible PETG infill

I'm at a loss.  Honestly even the perimeters from what I see don't look great.  I print with the Prusament profile all the time without issue. 

Have you ever printed abrasive filament?  Could you try swapping in a new nozzle to try? 

I assume your using a .4mm nozzle since that is what was in your 3mf.

Posted : 19/01/2025 3:46 am
FoxRun3D
(@foxrun3d)
Famed Member
RE: Terrible PETG infill

I'm at a loss. 

So true, unfortunately. I don't see a problem with your settings so it feels like a hardware issue. I don't understand why you appear to have good results with PLA and then this with PETG. If it were something mechanical I'd expect similarly crappy results with PLA. Swapping nozzles is a reasonable suggestion. Beyond that I'm running out of ideas. Maybe a thermistor issue? Not getting hot enough for PETG? 

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Posted : 19/01/2025 12:20 pm
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