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Collecting filament at the HF nozzle  

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chaoscrack
(@chaoscrack)
Eminent Member
Collecting filament at the HF nozzle

Dear all

I upgraded my MK4 to MK4S with HF nozzle.

Now I have print failure. There is molten filament collects at the nozzle. And from time to time this filament sicks at the print. When the print head comes back to this point, it stucks and tear the print off.

I use the standard profile of the filament and I tried it with prusament PETG and with extrudr PETG. At both filament I got fimamentcollecting at the nozzle.

Is there anybody with the same problem or has anybody an idea to solve the problem?

Thank you

Best Answer by ScottW:

I print mostly PETG and had the same issue with the HF 0.4 nozzle.  Back to the regular 0.4 nozzle, and no problems -- same filament, same models.

I suspect the issue is that retraction simply isn't as effective with the HF nozzle, and PETG exhibits this problem if retraction is not perfect.  But that's just speculation, as I haven't experimented -- I just went back to the normal 0.4 nozzle.

As someone else mentioned, other causes like wet filament, over-extrusion, and intersecting infill (such as the default Grid infill) can also cause "blobbing" like that with PETG.  But if you have only noticed it with the HF nozzle, then try switching back to the regular nozzle and see if the problem is resolved.

Posted : 03/12/2024 10:21 am
Thomas Lynch
(@thomas-lynch)
Estimable Member
RE: Collecting filament at the HF nozzle

Sounds to me like a defective nozzle 

l did the same upgrade and have had nothing but great prints 

Tom

Posted : 03/12/2024 2:56 pm
Brian
(@brian-12)
Reputable Member
RE: Collecting filament at the HF nozzle

PETG is super sticky and nozzle buildup is not uncommon, however it's typically made much worse by wet filament. 

Id recommend drying your filament, and making sure your nozzle is clean at the start of the print when it does bed probing. 

Posted : 03/12/2024 3:20 pm
ScottW
(@scottw)
Reputable Member
RE: Collecting filament at the HF nozzle

I print mostly PETG and had the same issue with the HF 0.4 nozzle.  Back to the regular 0.4 nozzle, and no problems -- same filament, same models.

I suspect the issue is that retraction simply isn't as effective with the HF nozzle, and PETG exhibits this problem if retraction is not perfect.  But that's just speculation, as I haven't experimented -- I just went back to the normal 0.4 nozzle.

As someone else mentioned, other causes like wet filament, over-extrusion, and intersecting infill (such as the default Grid infill) can also cause "blobbing" like that with PETG.  But if you have only noticed it with the HF nozzle, then try switching back to the regular nozzle and see if the problem is resolved.

Posted : 14/12/2024 6:37 pm
Klingenbeck
(@klingenbeck)
Active Member
RE: Collecting filament at the HF nozzle

Hi, I got the same issue with PETG. The solution for me was to set the extrusion multiplier to 0.93 and using 0.20mm STRUCTURAL @MK4S 0.4 profile. It's a workaround until the retraction will work with the HF 0.4 nozzle.

Regards

Posted : 17/12/2024 5:32 pm
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