How to Fix Zits and Blobs on 3D Print Surfaces
Small raised bumps or scarring on otherwise smooth surfaces, often appearing at the same spot on every layer where the nozzle starts a new loop.
Common causes
Pressure buildup released at the seam
As the nozzle finishes a loop and starts the next, built-up pressure in the nozzle can release as a small blob.
Ooze during the travel move to the next seam
Similar to stringing, but concentrated at one recurring point instead of stretched between features.
Aligned seam placement
If the slicer stacks every layer's seam at the exact same spot, any minor blobbing becomes one obvious visible scar line.
How to fix it
Enable coasting
This stops extrusion slightly before the end of a line, relieving pressure so it doesn't blob out at the seam.
Randomize seam position
Switch from an "aligned" seam setting to "random" or "nearest" so any blobbing gets scattered instead of stacked in one visible line.
Enable wipe on retract
Moves the nozzle briefly along the perimeter during retraction, wiping away built-up ooze instead of depositing it as a blob.
Fine-tune retraction settings
Adjusting retraction distance and speed can reduce the pressure spike that causes blobbing in the first place.
Still stuck?
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