How to Fix Ghosting and Ringing

Ghosting and ringing are the same family of defect: faint echoes or ripples that repeat a sharp edge, corner or letter on the surface next to it. Klipper's documentation calls the defect ringing (also known as echoing, ghosting or rippling) and says elements such as edges repeat themselves on the surface as a subtle echo. Prusa describes ghosting as several waves that follow after a sharp edge of a model.

The cause, according to Klipper, is mechanical vibration from quick changes of printing direction. Prusa adds that vibrations increase with print speed. So the fix is to make the machine stiffer, make the motion gentler, or have the firmware cancel the vibration.

Ghosting and look-alikes

1. Check the mechanics first

Klipper says ringing usually has mechanical origins: an insufficiently rigid frame, belts that are not tight or are too springy, alignment problems of mechanical parts, or heavy moving mass. It tells you to check and fix those first. Prusa's checks:

• Belt tension. Pluck the belt like a guitar string. Prusa says a belt should give a deep bass tone, with a tighter belt giving a higher tone. On MK3-family printers it says the belt status values in the LCD menu (Support, Belt Status) between 240 and 300 are fine. Lower means more tension.
• A firm surface. Prusa recommends placing the printer on a firm surface. A wobbling desk adds vibration. The enclosure advice in enclosed vs open-frame printers may also matter if panels or covers rattle.
• Loose parts. Tighten loose screws, pulleys and toolhead parts. Note that heavy toolhead changes move the resonance frequency, as Klipper points out for new motors or hotends.

Prusa also says ghosting can remain even when belts are properly tight, so do not keep tightening beyond the maker's guidance. Over-tight belts add load.

2. Reduce speed and acceleration

Prusa's general advice for ghosting is to reduce the printing speed and see whether the problem goes away. Acceleration has a similar effect, since quick changes of direction cause the vibration. Lowering outer wall speed and acceleration, as Bambu Lab suggests for smoothing other surface lines, is an easy test. The cost is longer print time. See print speed vs quality.

3. Use input shaping if your printer supports it

Klipper describes input shaping as an open-loop control technique that creates a commanding signal that cancels its own vibrations. Besides ringing, it typically reduces vibration and shaking in general. Tuning means printing a ringing test tower, measuring the ripple spacing, and setting the frequency in firmware. Klipper documents this in detail, and OrcaSlicer's wiki has a calibration workflow for Klipper and Marlin.

Points from those guides:

• Klipper's ringing test uses a layer height of 0.2 or 0.25 mm, 1 to 2 perimeters and external perimeter speed of around 80 to 100 mm/s.
• OrcaSlicer recommends an opaque, high-gloss filament so the ringing is easy to see, and a default test range of 15 to 110 Hz, with damping of 0.1 to 0.2 as a common start.
• If the measured ringing frequency is very low (below roughly 20 to 25 Hz), Klipper suggests stiffening the printer or reducing moving mass before tuning further.
• Klipper notes the ringing on the test print should follow the curved notches. If it does not, the defect has a different origin, mechanical or extruder related, which should be fixed first.
• OrcaSlicer suggests repeating calibration once a year or after changes such as relocation, a new support surface, belts, motors or frame.

Some printers have a built-in accelerometer that measures resonance automatically. OrcaSlicer's wiki says that if yours does, use it, as it can give more accurate results in less time. Klipper also warns that too much shaping can smooth parts and lose fine detail, so do not set acceleration higher than the printer can use well.

4. Quick check after each change

Print a small block with sharp corners and some raised text, in a glossy filament, and look at it under side light. Compare the echo size after each single change: tightened belts, lower acceleration, then input shaping.

Printer layout also matters: a lighter moving mass generally helps, which is one reason people compare CoreXY and bed-slinger printers and direct drive and Bowden extruders.

If the pattern is fine vertical lines on flat walls rather than echoes by corners, see vertical fine artifacts (VFA).