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Flex
 Flex
(@flex)
Eminent Member
PETG Issue

Hello

What could cause a change in extrusion just on a portion of the first layer? It also does on a portion of the second layer, but things go south since the filmnet won't stick on the portion. The filament is dry too. 

 

 

Best Answer by Flex:

I figured it out, and it's printing awesome now. First, you need to use structural printing, not speed, and second, under the extrusion multiplier, set to 0.97.  I was playing with the multiplier because of the blob build-up on the tip, and this is why I was under extursion. When @Raaz recommends slowing down. I changed to structural, that was the missing link. 

Posted by: @martinp

... I have seen issues at the first layers with PETG on my prints too. Blobs suddenly coming off...unclean layers like in your picture.

Seems to me like the higher faith of a religion (sounds funny but it's aint), that when sending the printfile out of the Prusa Slicer via Prusa connect to the printer, the issus don't appear. (I'm new to the printer but with a lot of technical understanding as a mechatronics engineer - so therefor there is only the G-Code and maybe no post processing through the Prusa Connect servers - so what could influence such a behaviour?!)

 

Napsal : 02/08/2025 3:49 pm
Raaz
 Raaz
(@raaz-2)
Reputable Member
RE: PETG Issue

First thing to test would be to reduce the first layer print speed massively. 

It's set to 40/100 mm/s iirc and that's way too fast in my experience for a nicely sticking layer. 

Try to reduce it to 15/30 and look if it's working better.

If not, there are issues. If yes, there are also issues, but not critical. 

Napsal : 02/08/2025 8:27 pm
1 lidem se líbí
Flex
 Flex
(@flex)
Eminent Member
Topic starter answered:
RE: PETG Issue

ok will try thx

Napsal : 02/08/2025 8:41 pm
MPdesign
(@mpdesign)
Active Member
RE: PETG Issue

... I have seen issues at the first layers with PETG on my prints too. Blobs suddenly coming off...unclean layers like in your picture.

Seems to me like the higher faith of a religion (sounds funny but it's aint), that when sending the printfile out of the Prusa Slicer via Prusa connect to the printer, the issus don't appear. (I'm new to the printer but with a lot of technical understanding as a mechatronics engineer - so therefor there is only the G-Code and maybe no post processing through the Prusa Connect servers - so what could influence such a behaviour?!)

Napsal : 03/08/2025 1:43 pm
Flex
 Flex
(@flex)
Eminent Member
Topic starter answered:
RE: PETG Issue

I figured it out, and it's printing awesome now. First, you need to use structural printing, not speed, and second, under the extrusion multiplier, set to 0.97.  I was playing with the multiplier because of the blob build-up on the tip, and this is why I was under extursion. When @Raaz recommends slowing down. I changed to structural, that was the missing link. 

Posted by: @martinp

... I have seen issues at the first layers with PETG on my prints too. Blobs suddenly coming off...unclean layers like in your picture.

Seems to me like the higher faith of a religion (sounds funny but it's aint), that when sending the printfile out of the Prusa Slicer via Prusa connect to the printer, the issus don't appear. (I'm new to the printer but with a lot of technical understanding as a mechatronics engineer - so therefor there is only the G-Code and maybe no post processing through the Prusa Connect servers - so what could influence such a behaviour?!)

 

Napsal : 03/08/2025 3:35 pm
2 lidem se líbí
Flex
 Flex
(@flex)
Eminent Member
Topic starter answered:
RE: PETG Issue

Here is what it looks like now. Perfect. 

 

Napsal : 03/08/2025 3:42 pm
3 lidem se líbí
Raaz
 Raaz
(@raaz-2)
Reputable Member
RE: PETG Issue

Great to see it's printing nicely now! 

When @Raaz recommends slowing down. I changed to structural, that was the missing link. 

If you want some more speed, try to only change the first layer speeds (and maybe travel speed, it's quite insane at 250 mm/s).

Additionally, you can use stealth mode, which for the Core One simply limits all speeds to 160 mm/s and reduces the acceleration values.
With my mk3s, stealth mode was activating some stealth mode in the motors/driver. Not so with the Core One!

Speed profile, stealth mode, first layer speeds to 20&40 mm/s instead of 40&100 mm/s and you should get nice and decently fast prints.

Napsal : 03/08/2025 7:47 pm
1 lidem se líbí
Flex
 Flex
(@flex)
Eminent Member
Topic starter answered:
RE: PETG Issue

Thanks, Raaz! I'm wondering why the Core One has this issue. I never checked the speed settings on my MK3S—maybe they weren't as fast? The MK3S never had this problem. I'm glad I upgraded and don't mind learning new things, but I was worried I'd made a big mistake with the upgrade.

Posted by: @raaz-2

Great to see it's printing nicely now! 

When @Raaz recommends slowing down. I changed to structural, that was the missing link. 

If you want some more speed, try to only change the first layer speeds (and maybe travel speed, it's quite insane at 250 mm/s).

Additionally, you can use stealth mode, which for the Core One simply limits all speeds to 160 mm/s and reduces the acceleration values.
With my mk3s, stealth mode was activating some stealth mode in the motors/driver. Not so with the Core One!

Speed profile, stealth mode, first layer speeds to 20&40 mm/s instead of 40&100 mm/s and you should get nice and decently fast prints.

 

Napsal : 03/08/2025 11:09 pm
Raaz
 Raaz
(@raaz-2)
Reputable Member
RE: PETG Issue

I never checked the speed settings on my MK3S—maybe they weren't as fast? The MK3S never had this problem.

Mk3s 0.2 mm speed profile lays down the first layer at just 20 mm/s.
Bambu Labs P1S runs the first layer at 50/105 mm/s with the X1C and P1S.
A friend of mine has a P1s and had massive issues with the final part of a big project. After debugging via video calls for an hour, he set the first layer speeds to 20/20 mm/s and the part printed perfectly.

Some parts simply don't really like to have the first layer laid down that fast..

Napsal : 04/08/2025 7:19 pm
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