Extruder blob - filament blob on printhead

Hey Bambulab printer fellows

. Recently, I faced an issue that led me on a bit of a quest for answers. Strangely, I couldn’t find any existing threads in our forum that addressed the same problem. So, here I am, ready to spill the beans and hopefully help someone out there who might stumble upon this dilemma.

During a faulty print, I found myself in a pickle. A rather sizable “blob” of filament had managed to accumulate under the nozzle and print head.

Why, you ask? Well, the print had detached from the bed mid-process. Yep, it happens.

Now, let’s get to the good part – the solution. The savior came from the Prosa Forum, and I’m excited to pass it on here, just in case someone’s currently in the same boat.
(Extruder blob | Prusa Knowledge Base)
So, here’s the drill:

  1. Abort the Print: Stop the print in its tracks.

  2. Lower the Print Bed: Bring down the print bed.

  3. Access the Nozzle: If possible, remove the front cover for better access.

  4. Heat Up the Nozzle: Heat the nozzle to about 30 degrees above the filament’s printing temperature (e.g., 250 degrees for PLA at 220 degrees).

  5. Melt the Blob: Wait around 5 minutes for the blob to soften against the nozzle.

  6. Power Down: Turn off the printer.

  7. Remove the Blob: Carefully extract the now-melted blob using pliers (be careful, it’s hot!).

  8. Cleanup: As per a tip from the Prusa Forum, I gently cleaned the nozzle with a copper brush.
    Alternatively you can do it like Rickey Impey showed in his video: (https://youtu.be/TCFOI5kUWQg?si=qVD3Zuhbc3kvKM2M) , by using a cloth to remove the molten filament residue. Keep in mind that the cloth might not be usable afterward.

Here are a couple of things you might want to avoid:

  1. Cold Removal: Trying to remove the filament blob when it’s cold can likely damage the nozzle.

  2. Heat Gun Approach: Using a heat gun to soften the blob is risky business, as it might damage other parts or even belts and guides.

If anyone has more tricks up their sleeve regarding this matter, please feel free to chime in. Sharing is caring, and together we can conquer those 3D printing conundrums!

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Lower it down to the build plate and turn on the plate heater as high as it’ll go, too. That’ll speed up how quick the plastic softens. Get it warm enough and it ought to just peel right off.

The few times this has happened to me over the years, I used my fingers rather than pliers. Yeah, you risk getting burned, but you reduce the risk that you’ll “over tweak” the extruder and damage it or the nozzle with the additional leverage pliers provide… Get any last little bit left by wiping down with a thick folded up piece of paper towel after the big chunk’s removed.


My problem is similar but the heat sensor is not working and it does not let me heat the nozzle. Any ideas?
Thank you

Fix the heat sensor.

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I would love to but not sure how. Everything is fused togeteher, i can’t even remove the cover.

That does not sound good.
Than you might have to heat the blob filament with a hot air gun or maybe with a Soldering iron.
You have to be super careful- this might harm your printhead electronics and cables.
Sorry I have no other solution for you.

I was afraid that would be the case

Did you soved your filament blob problem?