cooling fans are up to speed and position.
The top surface isn't thick enough.
Increase the top layer thickness in the
setting.
Insufficient supply. Check the machine to
make sure there are no loose parts.
The diameter of the filament changes,
resulting in insufficient supply.
Make sure the machine is running
smoothly, some lubricant may be applied.
The extruder makes an abnormal sound of
"Ka Ka Ka" during printing:
It may be that the nozzle is blocked, use a
needle to unclog it.
The quality of the filament is not high, you
can try another filament.
The temperature of the printhead is too
high, and the filament is carbonized into
small black particles. Turn down the
printing temperature a bit.
The torque of the feeding part needs to be
adjusted.
The extruded filaments look uneven/