Vertical Fine Artifacts (VFA) are subtle repeating bands on smooth walls. They are often blamed on “bad calibration,” but the pattern is usually tied to the motion system and can change dramatically with speed.
VFA vs. ringing vs. Z banding
Ringing starts after a corner or sharp feature and fades away. Z banding forms horizontal variation along the Z axis. VFA are typically vertical or slightly patterned and repeat across otherwise uniform walls.
Why speed matters
Stepper motors, belts, pulleys and the frame can excite repeating motion errors at certain speeds. A machine can therefore show stronger VFA at one wall speed and much cleaner surfaces slightly above or below it.
Run a speed sweep
A controlled VFA test that changes speed in sections is more informative than simply slowing the whole printer. Look for ranges where the pattern becomes stronger or weaker and compare those sections at the same lighting angle.
Mechanical checks
Inspect belt tracking, pulley alignment, loose set screws, damaged teeth, contaminated rails and abnormal bearing drag. Do not automatically overtighten belts: excessive tension can create its own problems.
Firmware and motor behavior
Input Shaper targets resonant ringing, not every source of VFA. Motor current, driver mode and motion implementation can also influence surface texture, but hardware changes should come after basic mechanical inspection and speed testing.
Do not confuse “less visible” with “fixed”
Matte filament, different lighting or a textured model can hide VFA without changing the motion error. For calibration, use a smooth test surface and consistent filament.
See also VFA in the glossary and the Troubleshooter for similar-looking artifacts.
