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Problem printing with petg  

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AvariCe
(@avarice)
Active Member
Problem printing with petg

Hello all,

when I try to print with petg (more specifically, my rolls are the prusa transparent purple petg and the red, green and blue transparent prusaments) this happens after some time:

I'm using an MK4, with the obxidian nozzle. I have attached the 3mf file for more info. Could you please help me troubleshoot this?

 

Thanks in advance

Best Answer by Brian:

 

Posted by: @volker

Looks like underextrusion. I had a simmilar problem with TPU. The filament was a bit sticking on the spool, leading to additional resistance which could not be compensated by nextruder. The MMU is passive once the nextruder has taken the filament. Try to unload some meter of filament manually and see if it's getting better.

You can also try to increase nozzle temperature or reduce max volumetric speed (filament advanced settings)

Infill prints faster than perimeters or to and bottom layers.  So I agree with underextrusion.

OP, look up the max speed for your filament and then convert that to a max volumetric speed in the filament profile. 

In addition increasing filament temperature by 10° C and possibly reducing the info speed. 

Try increasing temp first. I've found that not all PETG is created equal. 

Posted : 14/10/2024 6:37 pm
AvariCe
(@avarice)
Active Member
Topic starter answered:
RE: Problem printing with petg

I couldn't edit the OP, so I'll post it here.

The print was properly adhered to the bed, I couldn't find any lifted corner or something like that.

Posted : 14/10/2024 6:46 pm
Volker
(@volker)
Estimable Member
RE: Problem printing with petg

Looks like underextrusion. I had a simmilar problem with TPU. The filament was a bit sticking on the spool, leading to additional resistance which could not be compensated by nextruder. The MMU is passive once the nextruder has taken the filament. Try to unload some meter of filament manually and see if it's getting better.

You can also try to increase nozzle temperature or reduce max volumetric speed (filament advanced settings)

Posted : 15/10/2024 4:49 am
Brian and AvariCe liked
Thomas Lynch
(@thomas-lynch)
Estimable Member
RE: Problem printing with petg

Would also look at how you store your filament.

PETG is not easy to keep dry. I keep mine at between 20 and 30% relative humidity and that seems to work well 

Tom

Posted : 15/10/2024 10:12 am
AvariCe liked
AvariCe
(@avarice)
Active Member
Topic starter answered:
RE:

 

Posted by: @volker

Looks like underextrusion. I had a simmilar problem with TPU. The filament was a bit sticking on the spool, leading to additional resistance which could not be compensated by nextruder. The MMU is passive once the nextruder has taken the filament. Try to unload some meter of filament manually and see if it's getting better.

You can also try to increase nozzle temperature or reduce max volumetric speed (filament advanced settings)

Thanks for answering, I'll try both of your suggestions.

 

@thomas-lynch I store the filament in a box that at most has 15% humidity,

This post was modified 1 month ago by AvariCe
Posted : 15/10/2024 10:17 am
ScottW
(@scottw)
Reputable Member
RE: Problem printing with petg

 

Posted by: @avarice

 I store the filament in a box that at most has 15% humidity,

The photos 100% look like "wet filament" to me. You need to dry the filament at about 65C for a few hours, and then try again. 

I can say from experience filament (especially PETG and Nylon) is NOT always dry when received, even when it arrives vacuum sealed with a desiccant pack.  Storing at 15% will not remove existing moisture.  Best practice is to dry the filament, THEN store in a dry box.

Posted : 16/10/2024 8:25 pm
Brian
(@brian-12)
Reputable Member
RE: Problem printing with petg

 

Posted by: @volker

Looks like underextrusion. I had a simmilar problem with TPU. The filament was a bit sticking on the spool, leading to additional resistance which could not be compensated by nextruder. The MMU is passive once the nextruder has taken the filament. Try to unload some meter of filament manually and see if it's getting better.

You can also try to increase nozzle temperature or reduce max volumetric speed (filament advanced settings)

Infill prints faster than perimeters or to and bottom layers.  So I agree with underextrusion.

OP, look up the max speed for your filament and then convert that to a max volumetric speed in the filament profile. 

In addition increasing filament temperature by 10° C and possibly reducing the info speed. 

Try increasing temp first. I've found that not all PETG is created equal. 

Posted : 17/10/2024 1:48 am
AvariCe liked
AvariCe
(@avarice)
Active Member
Topic starter answered:
RE: Problem printing with petg

 

Posted by: @volker

Looks like underextrusion. I had a simmilar problem with TPU. The filament was a bit sticking on the spool, leading to additional resistance which could not be compensated by nextruder. The MMU is passive once the nextruder has taken the filament. Try to unload some meter of filament manually and see if it's getting better.

You can also try to increase nozzle temperature or reduce max volumetric speed (filament advanced settings)

Posted by: @brian-12

 

Posted by: @volker

Looks like underextrusion. I had a simmilar problem with TPU. The filament was a bit sticking on the spool, leading to additional resistance which could not be compensated by nextruder. The MMU is passive once the nextruder has taken the filament. Try to unload some meter of filament manually and see if it's getting better.

You can also try to increase nozzle temperature or reduce max volumetric speed (filament advanced settings)

Infill prints faster than perimeters or to and bottom layers.  So I agree with underextrusion.

OP, look up the max speed for your filament and then convert that to a max volumetric speed in the filament profile. 

In addition increasing filament temperature by 10° C and possibly reducing the info speed. 

Try increasing temp first. I've found that not all PETG is created equal. 

Thank you both gentlemen, apparently it was underextrusion. I increased the temperature in steps of 5C and it worked really well at +10C. Thanks again.

Posted : 17/10/2024 3:10 pm
Brian liked
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