How to work with PETG? Settings, caveats, etc

  • We've been doing some printing with PETG filament on Ender 3 Pro printer and the result were awful:
    Overview of failed PETG prints

    Here are settings we used:

    • Extruder: 240 °C

    • Bed: ~70 °C (± 10 °C)

    • Speed: 80 mm/sec

    There are a few types of problems that we had:

    1. Initially filament did not stick to the bed - those 3 items in the middle of the picture are example of this issue. This got fixed by increasing temperature of bed to 80 °C.

    2. At some point a piece would get dis-attached from the bed and would move around together with the extruder around - two prints in the upper right corner of the picture were cancelled for this reason.

    3. Models are very rough, like a cheaply made snowball - that tiny model in the upper left is suppose to be a cattle-bell. Could you tell?

    Additional info

    Filament that we used indicated

    • extruder temperature 230-240 °C

    • printing speed 40-90 mm/sec

    • no info about bed temperature


    • What are some optimal, tried and tested options for printing PETG? (Temperatures, speed, etc)

    • What are some caveats/difficulties of working with PETG to look out for? (For example, I've read that PETG likes slower speeds. Is that true?)

    • Is it possible that the model of 3D printer does not work well with this type of filament? (I don't have much experience printing so I can't know)

  • wha7ever

    wha7ever Correct answer

    3 years ago

    The real problem was that I damaged the nozzle (most likely while cleaning it) in a way that increased the size of the hole. So, too little filament was coming out of too big of a hole, which caused such poor models. Replacing the nozzle fixed the problem.

    I do not remember the settings of the top of my head. Generally advised settings for PETG (whatever they were) worked fine.

    How did that happen?

    @FarO Probably while I was using scissors-like instrument (I forgot how it is called) to clean up excess of filament that was coming out during warmup. I must have not been careful and cut off a tip of nozzle by accident. I didn't notice while I was doing it. That thing is so tiny. But looking back at what I was doing this would make the best sense. I was also trying to level the bed and used piece of paper to determine friction. Not sure if that could do any damage to the nozzle's tip (if not done carefully).

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Content dated before 7/24/2021 11:53 AM