Blobs and Zits
Reduce small bumps and marks appearing on otherwise smooth walls.
Blobs or zits are small deposits of extra material on the outside of a print.
They often occur where each perimeter begins or ends.
First, check whether the marks form a vertical line. If they do, they are probably related to the Z-seam.
Most slicers allow you to control where the seam is positioned. Moving it to the rear or a sharp corner can make it less noticeable.
Incorrect pressure control, retraction or flow settings can increase seam blobs.
Excessively high nozzle temperature can also increase oozing.
Wet filament can cause random surface imperfections because moisture turns into steam inside the hot end.
Try drying the filament if the surface also contains bubbles or popping sounds are heard during extrusion.
Modern printers may support pressure advance or flow-dynamics calibration, which can improve starts and stops.
Common causes: Z-seam placement, high temperature, wet filament, poor pressure advance, incorrect retraction.