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Burned blobs and oozing  

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Robert Stárek
(@robert-starek)
New Member
Burned blobs and oozing

Hello,

I am a new user of the Prusa i3 MK3 printer and I encountered some issues:

a) The filament is oozing from the nozzle during Z-calibration and remains on the priting bed as strings of filament. I can clean them during calibraion, so this is just a minor issue.
b) The worse part is that the printer randomly produces "burned blobs", see the attached photo. I really do not know how this is caused.

  • Filament: Prusa PLA 1.75mm (orange)

  • Nozzle: The original nozzle (brass 0.4 mm)

  • Preheat settings: 60 °C print bed, 215 °C nozzle.
  • Prusa Slic3r settings:

  • Material: Prusa PLA

  • Print settings: 0.05mm DETAIL MK3

  • Printer: Original Prusa i3 MK3
  • In the case of the attached photo I did not change any advanced settings.

    Did anybody encountered similar problem? Would cleaning the nozzle help?

    Later I also tried to increase retraction length from 0.8mm to 0.9mm. It seems that it helped reduce oozing but the printer still produces these burned blobs, see the second attached photo.

    Recently I changed the nozzle and before I encountered this issue I mounted back the original nozzle. Could something go wrong with heater? Could the nozzle be improperly screwed?

    Posted : 26/06/2018 12:11 pm
    Gato
     Gato
    (@gato)
    Reputable Member
    Re: Burned blobs and oozing

    Did this spool use to print fine? Have you tried with another spool? I'm asking this since I had a spool that printed fine and after using half of it, it started to leak from the noozle and produce more ooze/strings than before. The problem (in my case): PLA filament started to absorb moister. Relative humidity in the room is about 48% and PLA was stored in vacuumed bag with desiccants. However, after leaving it on the spool holder for a few weeks this black PLA was giving me all this trouble "out of nowhere". I built a DIY filament dryer, "cooked" the filament for 5 hours and then gave it a new try. It prints like new. Again, no print settings where changed. Only variable that changed was dried filament.

    Posted : 26/06/2018 6:25 pm
    Martin Wolfe
    (@martin-wolfe)
    Reputable Member
    Re: Burned blobs and oozing

    You could just try reducing your print temperatures.

    Regards,
    Martin

    Martin Wolfe

    Posted : 27/06/2018 12:36 am
    Robert Stárek
    (@robert-starek)
    New Member
    Topic starter answered:
    Re: Burned blobs and oozing

    I will give it a try.
    Thanks for your advices. The without it I would not take moisture into account before. I store my PLA openly in the room.

    R.

    Posted : 01/07/2018 6:29 pm
    Daniel
    (@daniel-32)
    New Member
    Re: Burned blobs and oozing


    Did this spool use to print fine? Have you tried with another spool? I'm asking this since I had a spool that printed fine and after using half of it, it started to leak from the noozle and produce more ooze/strings than before. The problem (in my case): PLA filament started to absorb moister. Relative humidity in the room is about 48% and PLA was stored in vacuumed bag with desiccants. However, after leaving it on the spool holder for a few weeks this black PLA was giving me all this trouble "out of nowhere". I built a DIY filament dryer, "cooked" the filament for 5 hours and then gave it a new try. It prints like new. Again, no print settings where changed. Only variable that changed was dried filament.

    gaston.d3, thank you for your post. I’m having similar ooze problems and suspect moisture as the cause. I’m curious about your DIY filament dryer. Could you direct me to build instructions or give a simple description that might help me build one?

    Many thanks,

    Daniel

    Posted : 27/07/2018 4:43 pm
    Gato
     Gato
    (@gato)
    Reputable Member
    Re: Burned blobs and oozing

    I got the Flexzion Dehydrator for Food Fruit and followed this video that explains very clearly how to customize it for our needs.

    Used it for a few filaments and worked very well.

    Posted : 29/07/2018 9:54 am
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