PETG-HF 0.6 nozzle big gaps at the seams

Elegoo Rapid PETG used to print like PLA with 0.6 nozzle after I tuned it, but something has changed and now it prints like ■■■■. So I bought some Bambu PETG-HF, the result is much better with a bit of stringing and tiny bubbles. The major issue is that it seems to be under extruding near the seams, resulting in large gaps. Exact same print with Elegoo does not produce gaps.

The filaments were dried in dedicated filament dyers for 8-12 hours prior printing and also during the printing too which still can’t get rid of stringing and tiny bubbles.

Any idea what is going on here? These are printed on P1S using Bambu PETG-HF profile. Interestingly, printing small parts with the exact settings seems to be less affected.

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You need to go back to tune the pressure advance (K - value) as its falling short.

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I calibrated it with both flow and k-value, and it improves the result but doesn’t completely eliminating the gaps. But it made the overall print worse than default BBL filament profile.

I think 0.6 nozzle and large parts are factors here. Same filament prints small parts just fine with 0.4 nozzle. With large part with a print time over two hours and 0.6 nozzle, there are gaps at the seam, small bubbles and occasionally tumors from goo buildup at the tip of nozzle.

No issues printing ABS & ASA of the same large part with 0.6 nozzle.

Reducing Temp and retraction helped in my case. Try to dry your filament, and print it out of a drybox if possible.

As a compromise, you could try to increase layer height with an .4mm nozzle…

I’ve confirmed the culprit is the printer profiles. Bambu Lab almost perfected 0.4 printer profiles, but any other nozzle size are roughly tuned for PLA. Long story short, it has to do with tuning printer profile’s retraction, temperature and speed parameters for each filament type. Confirmed! 0.6 and 0.8 printer profiles suck!

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What exactly did you change for retraction/temp? I have a the same issue with PETG-HF and certain PLA at 0.4. The parts after de-retraction are always under-extruded

Could you share the printer settings you used. I’m having the same issue but want to use a .6 nozzle.

Guys, I had this same issue and discovered that this issue can be caused by having back to back seams in the same area on a box corner (like if its only a few walls thick). I turned off “wipe while retracting” and moved the inside seam somewhere else and slowed down the outer wall acceleration to 2500mms. 0.6mm nozzle, grey petg, H2C printer.

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I will try this. I’m having the same issue with 0.6mm HF nozzle on H2C with PETG-Translucent.

PA/Dynamic Flow -Calibration doesn’t help and the default profile leads to formation of blobs at the beginning of new layers/after travel but also underextrusion at seams

Automatic pressure Advance doesn’t work good. I raised white flag on that. Do it yourself for a given temperature in a span of a minimum and maximum printing speed and gl… If you deviate from those given fixed points of your choice you probably need to retune everything.

I recently started to print 0.2 instead of 0.16, I had to change k and even flow rate to continue to print at 275°c, otherwise I got defects

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