Ghosting and ringing: echoes around corners and text

This guide is for anyone seeing wavy shadows on the walls of otherwise clean prints, usually just after corners, holes or lettering. It explains what causes them, which mechanical checks makers suggest, and how Prusa, Bambu Lab, Creality and Klipper describe input shaping and vibration compensation. It also covers the slicer speed and acceleration settings that OrcaSlicer, Cura and Simplify3D document.

What do ghosting and ringing look like?

Prusa says ghosting "can be typically recognized by several waves that follow after a sharp edge of a model." Klipper's documentation describes ringing (which it says is "also known as echoing, ghosting or rippling") as a defect where "elements like edges repeat themselves on a printed surface as a subtle 'echo'." Polymaker uses the same idea: details "can be seen outside where they should be."

Simplify3D explains why it appears where it does. When the extruder makes "a sudden direction change, such as near a sharp corner," the inertia of the moving parts "can create vibrations," and those vibrations are printed into the wall.

Ghosting or something else?

Several defects make walls look uneven. Where the pattern sits tells you which one you have:

What causes ghosting?

Klipper's documentation says ringing "usually has mechanical origins," and lists an "insufficiently rigid printer frame, non-tight or too springy belts, alignment issues of mechanical parts, heavy moving mass, etc." It says these "should be checked and fixed first, if possible." The makers' guides add speed and acceleration to that list.

Speed and acceleration

Simplify3D calls moving too fast "the most common cause for ringing," because sudden direction changes "create additional force that can cause the lingering vibrations." Prusa says ghosting "is caused by vibrations that increase with print speed."

Polymaker puts acceleration and jerk first. It calls high acceleration and jerk "the number one reason this occurs," and says some printer makers set defaults high so they can advertise faster print times. In its comparison print, lowering acceleration from 3,000 to 500 and jerk from 30 mm/s to 12 mm/s, with every other setting the same, made "a drastic difference," and added about 14 minutes to a print of roughly an hour and a half.

Loose belts, and belts that are too tight

Prusa's first fix is belt tension on the X and Y axes. Bambu Lab explains why tension matters on its X1 and P1 series printers: the belt and gantry act as a spring and mass, and "a loose belt reduces the k, and the f, which in turn affects vibration compensation."

Polymaker adds the opposite warning: belts that are too tight "can cause ghosting" too, because overstretching reduces damping. Follow your printer maker's tensioning procedure rather than simply cranking the belts tighter.

Frame rigidity and the surface under the printer

Simplify3D suggests looking for "a loose screw or a broken bracket" if speed and acceleration changes don't help. Prusa says "it's always better to place the printer on a firm surface," and Creality's K1 manual warns against exposing the printer to "violent vibration or any other unstable environment, as this may cause poor print quality."

Polymaker offers a different angle. It says small foam cushions under the printer's feet can help disperse vibration, and that a very rigid frame without axis dampening or input shaping can leave vibrations with nowhere to go. Prusa and Creality focus on a firm, stable base; Polymaker's cushions are an option to test, not a replacement for a stable table.

A heavy toolhead or bed

Polymaker says "the lighter the carriage, the less ghosting you will experience," so a direct-drive extruder can show more ghosting than a Bowden setup. It also says ghosting "should be reduced on a CoreXY or Delta machine," because moving a heavy bed on a bed-slinger makes it worse. Klipper notes that changing the toolhead's mass, adding glass to the bed of a bed-slinger, or tightening belts can all change the ringing frequency, so remeasure after those changes.

Step 1: Check the mechanics

Start with the free checks:

• Prusa MK2/2.5/S and MK3/S: Prusa's ghosting article suggests plucking the belt "like a guitar string." It should give "a deep bass tone." It also points to the Belt Status values in the printer's Support menu, where it says values between 240 and 300 are fine, and a lower number means a tighter belt.
• Prusa MINI/MINI+: Prusa says the belts should be tight enough "to sound like a low bass note when plucked," and links its MINI belt adjustment guide.
• Bambu Lab X1 and P1 series: Bambu's belt tensioning procedure covers both series. It says cleaning the carbon rods and tensioning belts "can change the resonance characteristics of the printer's toolhead," so the printer "should be recalibrated afterwards."
• Creality K1 Max: Creality's ringing guide lists three causes: belt tensioning, "insufficient lubrication of the XY-axis," and "external interference during vibration optimization." It shows how to check whether the left and right tensioning screws have been released, and how to clean and grease the X and Y axes.
• Any printer: Simplify3D suggests watching the printer run to see where the vibration comes from. Check the table or bench too.

Step 2: Run input shaping or vibration compensation

Many newer printers measure their own resonance and cancel it in firmware. Polymaker says printers with "input shaper" or "vibration compensation" calculate a way to compensate for these vibrations, which is why they can print fast without ghosting. Each maker documents its own version.

Bambu Lab: vibration compensation

Bambu Lab's calibration guide lists vibration compensation among the auto-calibration items and says to run calibration after moving the printer, because "the printer maps vibration patterns on the new surface" and then cancels them "during fast movements, preventing ghosting and ringing artifacts." It also says to calibrate after firmware updates, belt tensioning or other maintenance, and when any hardware part changes. The guide gives screen paths for the X1, P1, A and H2 series and the P2S and X2D, and you can also start calibration from Bambu Studio or Bambu Handy.

For a ringing effect on the outer walls, Bambu's X1 troubleshooting page says the belts "need to be re-tensioned and the Vibration Compensation needs to be calibrated again." Its second suggestion is to lower the acceleration under Speed → Acceleration → Normal Printing.

Prusa: Input Shaper

Prusa says Input Shaper is "designed to reduce ghosting by canceling resonance vibrations." It arrived with firmware 5.0.0 on the MK4 and firmware 5.1.0 on the MINI/+ and XL. Prusa says the CORE One family, MK4S, MK3.9/S and MK3.5/S also have it. Two points from Prusa's article:

• You need the right profile too. Prusa says Input Shaper needs both the right firmware and an Input Shaper profile in PrusaSlicer. Non-Input-Shaper profiles have moved to the Legacy category.
• Recalibration is usually unnecessary on a stock printer. Prusa says Input Shaper is pre-calibrated at the factory. If you've modified the hardware, it may be worth recalibrating with an accelerometer. The CORE One L and XL have one built in; on other models it's optional.

Prusa also suggests basic maintenance first: make sure the X and Y belts aren't loose, the nozzle is in good shape, and there's no debris on the smooth rods.

Creality K1 Max: rerun Input Shaping

Creality's K1 Max ringing guide says to rerun Input Shaping from Settings → Device Self-inspection, tick Input Shaping, then tap Start Detection. It estimates about 3 minutes. Creality adds: "please place the machine in a sturdy and vibration-free environment" while it runs.

Klipper printers

Klipper's resonance compensation documentation calls input shaping "an open-loop control technique which creates a commanding signal that cancels its own vibrations." It says tuning needs measurements first: its basic method prints a ringing test tower, and it notes that an accelerometer can measure the resonances instead, though fitting one "requires some crimping and soldering." Points worth knowing before you start:

• Fix the mechanics first. If the measured ringing frequency is "very low (below approx 20-25 Hz)," Klipper suggests stiffening the printer or reducing the moving mass before further tuning.
• Too much acceleration causes smoothing. Klipper says that at very high accelerations input shaping "may cause too much smoothing and rounding of the parts," so max_accel should be chosen to avoid that. It also advises against raising square_corner_velocity above the default 5 mm/s.
• Ringing can come back. If it returns after a while, Klipper says the frequencies may have changed, for example because a belt has loosened, so remeasure.

OrcaSlicer's calibration test

OrcaSlicer has an input shaping calibration for printers whose firmware supports it. It suggests using a printer's built-in accelerometer if it has one, because that "can provide more accurate results in less time." Otherwise, it prints a ringing tower across a range of frequencies (15–110 Hz by default), then a damping test, and you save the results to your firmware and printer profile. It recommends an opaque, high-gloss filament to make ringing easier to see. OrcaSlicer suggests repeating the calibration "once a year or after any mechanical or structural changes such as relocation, changing the support surface, new belts, motors, frame, etc."

Step 3: Lower acceleration in the slicer

If your printer has no input shaping, or ghosting remains after calibration, slow the moves that make outer walls. Polymaker says nearly every slicer now lets you change acceleration, so you don't need to edit firmware. Simplify3D says firmware acceleration controls are "vital for preventing ringing," and that lowering them makes speed changes more gradual.

• OrcaSlicer: Separate accelerations for outer wall, inner wall, bridges, infill, top surface, initial layer and travel. Its wiki says outer wall acceleration "is usually set to a lower value than normal printing to ensure better quality," and that Orca won't exceed the limit in the printer's Motion ability settings.
• Bambu Lab: Its X1 troubleshooting page says to lower the acceleration under Speed → Acceleration → Normal Printing.
• Cura: Turn on Enable Acceleration Control and Enable Jerk Control in the Speed section, then lower Outer Wall Acceleration and Outer Wall Jerk. Cura's descriptions of the two Enable settings say that increasing acceleration or jerk "can reduce printing time at the cost of print quality."
• Simplify3D: Lower Default Printing Speed and X/Y Axis Movement Speed on the Speeds tab. Simplify3D says you may need to adjust both.

Lower the outer wall first, since that's the surface you see. Inner walls and infill can usually stay faster.

A sensible order

1. Confirm it's ghosting: ripples that fade out after corners or features, not regular bands or a sideways shift.
2. Put the printer on a firm, stable surface and check for loose screws or brackets.
3. Check belt tension using your printer maker's procedure.
4. Rerun input shaping or vibration compensation if your printer has it, especially after moving it or adjusting belts.
5. Lower outer wall acceleration (and jerk, where your slicer offers it), then speed.
6. If you've changed the toolhead, bed or frame, recalibrate.

When not to buy parts

Ghosting is usually fixed with settings, belts and placement. Before buying anything:

• Recalibrate after a move. Bambu Lab and OrcaSlicer both say moving the printer or changing what it stands on is a reason to recalibrate.
• Accept a little. Polymaker notes that a part with minor ghosting "is still entirely useable." If the ripple is faint and only on test cubes, slower outer walls may be all you need.
• Check the belts before blaming parts. Polymaker says belts that are too loose can cause Z wobble "or even layer shifts." If you see layer shifting as well as ghosting, start with the belts.

If ghosting persists on a printer that has input shaping, and the belts, surface and calibration all check out, contact the printer maker's support.

Tools: what to check before you buy ↗