Ripple patterns on vertical walls, concentrated after sharp corners. The ripples diminish in amplitude as they move away from the corner — they start pronounced at the corner and fade into the wall over 10–20mm. This is the same phenomenon as ghosting. Both terms describe printer frame resonance imprinted on the surface.
See the Ghosting / Ringing guide for the full diagnostic and fix sequence — the two guides cover the same problem.
Quick Summary
Primary causes: Loose belts, high acceleration, high print speed, mechanical play in the motion system.
Fastest fix: Reduce acceleration to 1000–1500mm/s² and reduce outer perimeter speed to 30–40mm/s. This usually reduces the artifact enough to see whether further mechanical tuning is needed.
Permanent fix: Enable input shaper in Klipper (requires an accelerometer to measure resonant frequency). Input shaper can effectively eliminate ringing even at high speeds. For Marlin, Linear Advance helps but doesn’t directly address ringing — reduce acceleration instead.
Mechanical fixes before software: Tighten belts (especially X-axis belt on cartesian printers). Check for loose carriage screws, worn bearings, and loose frame bolts. All of these create play that amplifies resonance.
Surface placement: Place the printer on a heavy, stable surface. A printer on a hollow table or lightweight shelf vibrates sympathetically with the frame. A heavy rubber mat reduces floor-coupling vibration.