Surface artifact can possibility caused by:
1) Over extrusion
Check out over extrusion issue.
2) Ghosting / ringing effect
Printing speed too high can cause the ringing effect on the surface. Check print setting, Lower printing speed or outline/outer wall printing speed may help.
3) Z banding/ribbing
Check out Z banding/ribbing.
4) X or Y Axis Shifting
Check out Layer Shift
5) Vertical lines on the serface
Could be POM bearing/wheels too loose or too tight. If it appear on the X side, move the X cariage, left and right; for Y side, move the platform back and forth and feel if there’s any bumpy effect, if there is, there are one or more POM bearing/wheels maybe too tight. Adjust the eccentric nut to loosen it slightly.
6) Salmon skin artifact
Install TL-Smoother may help fix the salmon skin artifact issue.
7) Filament thickness inconsistent (rare case)
Most filament in the market shouldn’t have problem, unless it is very bad in quality.
Share with us how you fix the over extrusion issue.