PerfectLayer3D

Ringing and ghosting: getting rid of ripples on FDM print walls

Assessed from documentation · Content verified on October 6, 2026

Where to start

  1. Waves repeating corners and lettering suggest ringing; uniform lines can have other causes.
  2. Check the support surface, play and belts before changing speed or acceleration.
  3. After mechanical adjustments, repeat vibration calibration if your model supports it.
Ringing and ghosting: getting rid of ripples on FDM print walls
Illustration of the defect, not a test photograph. Shapes are simplified.

How to recognise ringing

Ringing, also called ghosting or “echoing”, is a series of ripples on the wall surface that repeat a detail just printed: a corner, a hole, an embossed letter. The ripples appear right after the detail, in the direction the toolhead is moving, and fade after a few millimetres. On a square part they usually show up next to the corners.

The Klipper documentation explains it this way: ringing is caused by mechanical vibrations of the printer due to quick changes of printing direction. So it should not be confused with other defects: regular horizontal lines on every layer (Z-axis or extrusion problems), fine, dense, uniform vertical lines across the whole wall (so-called VFAs, linked to motors and belts, for which some printers have a dedicated calibration), or variations from infill showing through. In the Bambu Lab forum an experienced user pointed out exactly this distinction to someone who thought they had ghosting.

Checks in order

Fix the mechanics first, then recalibrate: input shaping only compensates for the frequencies it has measured, and any work on belts or rails changes them. Switch the printer off and let it cool before touching the toolhead, bed or belts: the nozzle and bed can be very hot.

  1. Check the surface: rigid and stable, all feet touching down, no contact with walls or other objects. Remove or secure anything that rattles (external spool holder, loose cables, loose panels).
  2. With the machine off, check frame, toolhead carriage and bed screws: try moving each part by hand to find play.
  3. On machines with eccentric wheels (many Creality and Anycubic bed-slingers), adjust the wheels until there is no play but motion stays smooth, as described in Anycubic's gantry calibration guide.
  4. Check and adjust belt tension with the official procedure: spring tensioner (Bambu Lab, Creality K1), frequency-measuring app (Prusa) or your manual's instructions. Don't overtighten: Bambu Lab warns that overtightening gives no better result and can cause damage.
  5. Follow the manual for cleaning and lubrication. Clean Bambu carbon rods without oil or grease.
  6. Rerun vibration calibration from the printer menu, with the machine standing still on a stable surface and not bumped during the test.
  7. Print a simple test model and, if ringing remains, lower outer-wall acceleration and speed in the slicer, one change at a time.

Brand notes: Prusa, Bambu Lab, Creality, Klipper and others

Prusa: Input Shaper is available on the CORE One, MK4/S, MK3.9/S, MK3.5/S, XL and MINI/+ with up-to-date firmware and requires PrusaSlicer's Input Shaper profiles. Before using it Prusa recommends X and Y belts that are not loose, a nozzle in good condition and clean rods. The CORE One L and XL have a built-in, factory-calibrated accelerometer; an optional accelerometer is available for other models and recalibration is recommended only after hardware changes. MK4 belt tension is checked with the official app that measures the belt's frequency; Prusa lists ghosting and non-round circles among the effects of loose belts.

Bambu Lab: the printers run a frequency sweep during calibration and also use it to detect when belts need re-tensioning (X1/P1 and A1 prompt for it). The procedure is: printer off, loosen the tensioner screws without removing them, move the toolhead to even out the tension, retighten; after tensioning or cleaning the rods, rerun vibration calibration.

Creality (K1 Max, K1C): check that the left and right tensioners have not been released, clean and lubricate the XY axes and rerun Input Shaping from the self-check, with the machine on a solid, vibration-free surface. Klipper: check the mechanics before tuning the input shaper; tune it with a test tower or an accelerometer, choosing a maximum acceleration that does not round corners too much. Other brands, such as Flashforge on the Creator 5, have a “vibration compensation” calibration in the menu.

When replacing a part is justified

In most cases ringing is fixed with adjustments and calibration, without spare parts. A replacement is justified when you find a genuinely damaged component: a belt that is frayed, missing teeth or stretched beyond adjustment; a pulley with a set screw that won't hold or that is worn; eccentric wheels that are worn or have play that adjustment won't remove; damaged bearings or rails.

If calibration keeps reporting abnormal frequencies after all the checks, or the defect appears on one axis only even though belts and pulleys are fine, contact the manufacturer's support before buying parts: as the Prusa forum cases show, some problems come from assembly issues or defects covered by warranty.

How to verify the result

Record the model and variant, material, slicer profile and change made. Repeat the same test and compare the result with a photo taken before the adjustment. Keep the change only if it improves the defect without introducing others. Use your model’s instructions for temperatures, calibration and disassembly; this guide is not based on our own hands-on tests.

Causes

Klipper lists the mechanics as the first thing to check: a frame that is not rigid enough, loose or springy belts, misaligned parts and high moving mass on the toolhead. Creality, for the K1 Max and K1C, lists three causes: belt tensioning, insufficient lubrication of the XY axes and external interference during vibration calibration. Prusa names loose belts and misaligned motor pulleys among the causes of an Input Shaper calibration that reports abnormal frequencies.

Bambu Lab explains the link between belts and compensation clearly: the belt and the toolhead form a mass-spring system whose natural frequency depends on belt tension. A loose belt lowers that frequency, so the previously calibrated compensation is no longer correct. Add to these an unstable surface (a light or wobbly table, feet not touching down), objects rattling on the machine, and accelerations higher than the mechanics can handle.

What users report in the forums

In the Prusa forum, several MK4 users with obvious ringing reported that belt and surface checks were not enough, while much lower outer-wall speed and acceleration almost eliminated the defect (at the cost of slightly rounded corners); the firmware release with Input Shaper was described as a big improvement. Some cases were only solved with hardware work, such as tightening the heater block, or through warranty service.

In another thread a user had more ringing with Input Shaper on than off: other users and Prusa support suggested checking belts, pulleys and mechanical alignment, because input shaping only corrects resonance effects, not mechanical faults. In the Bambu Lab forum users recommend simple test prints (cubes, cylinders) to isolate the cause and telling ringing apart from other artifacts. The most common mistake is trying to fix everything with slicer settings without checking the mechanics first.

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