Clumping during prints

Hi everyone, I’ve been running into a weird phenomenon recently that I can’t figure out the cause. During printing, I’ll get sporadic clumps on a layer. These usually don’t mess up the print, but the excess typically ends up on the hot end nozzle. This has happened with different filament types and from different manufacturers. Has anyone else run into this or know the cause?


First off, it looks like the nozzle is too close to the build surface. On top of that, one or more of the following may also be an issue:

  1. The temperature of the hot end may be too high for the filament that you are using.
  2. The filament that you are using might be bad, try a different/better brand.
  3. There might be something stuck in the nozzle (unlikely though).

Items #1 & #2 can feed into each other, so it’s always best to try at least 1 other filament brand that is known to be good, while testing. Some bad filaments require higher temperatures in order to flow smoothly, but their chemical makeup isn’t able to withstand the higher temperature, which makes them clump like that. I am not saying that this is exactly what is happening, but it is 1 possibility.

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