Extruder Blob

Updated 3 months ago ​by Tomáš Chvalina

So you've let your printer run overnight, and you wanted to see what amazingness it has printed. Instead, you have found a mass of extruded filament around the Extruder, also known as a BLOB.

What's likely happened is during the print, the print became detached and stuck the nozzle. The extruder kept extruding and the blob grew and grew, leaving you with a non-working printer.

Relax, keep calm, it's not as bad as it seems. We will show you how to get going again, simply follow the instructions below and check out the video "How to remove a stuck blob of extruder filament."

How to deal with the extruder Blob

  1. You need to keep in mind what can be entangled in the mass/blob that has formed around the hot end, which are the leads for the thermistor and heater cartridge. The leads for the thermistor are the ones to be most careful with as they are thin gauged wires.
  2. We now want to preheat just the nozzle which you can do in the LCD Menu - Settings - Temperature - Nozzle. Depending on the material you are using, it will require a different temperature. In any case, you want to have significantly hotter than your print temperatures. For example, if the blob is made of:
    1. PLA: preheat to 250°C
    2. ABS/PETG: preheat to 280°C
  3. Would any of the leads be broken at the very start? You can be given MINTEMP or Preheat error. Then you are left with one last option, which is the heat gun. Work very carefully with it and only clear bits of plastic at once.
  4. Once the hotend is up to the set temperature, using a pair of pliers, carefully work the newly molten areas of the blob-free. Again, be very cautious around the leads coming from the hot end, in particular, the thermistor leads.
  5. Work slowly and cautiously around the mass, no need to rush it. Doing so will likely result in having to purchase replacement parts.

Unfortunately, some of the Blobs are not really easy to clear. Especially the ABS/PETG ones. Would you not be successful you can find spare parts at our e-shop (remember that you must be log into your e-shop account) MK2 spare parts. 

How to prevent extruder Blob happening 

  1. It usually happens once the First layer did not stick to the Heated bed properly. And after a couple of minutes, it detaches and gets caught around the extruder.
  2. So always stay around the printer for 5-10 minutes (depending on the size of your print). Best practice is to leave the printer only if you can clearly see that First layer sticks perfectly. 
    1. You can find more about that in 1st layer calibration (Live Z adjust) and Increasing PEI adhesion
   Just for the reference. That is what you can find at our Printing farm. :)

As always, if you have further questions, concerns or encounter any problems, please contact our support team at info@prusa3d.com.

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