Input Shaping Explained: Less Ringing, Faster Prints

Input shaping is a motion-control technique that reduces ringing on 3D prints by shaping the printer's movement commands so the vibrations they cause cancel each other out. It is a firmware feature in Klipper, Marlin and Prusa firmware, and it lets you print faster without ripples next to sharp corners.

This guide explains how it works, what the shaper types mean, and what it cannot fix. Everything here comes from firmware and slicer documentation, listed under Sources, not from our own printing.

What is input shaping in 3D printing?

Input shaping is an open-loop control technique for reducing vibrations in computer-controlled machines, according to the general definition on Wikipedia. The controller builds a command whose later parts produce vibration that offsets the vibration from its earlier parts. Marlin's documentation puts it the same way: it cancels the dominant frame resonance, the "ringing", by timing part of the motion pulses to coincide with ringing from earlier pulses.

On a printer, the resonance is the frame, gantry or bed wobbling at a natural frequency after a sudden change of direction. That wobble is copied into the plastic as faint ripples, usually called ghosting or ringing. If you are seeing those ripples now, start with how to fix ghosting and ringing.

How does input shaping work?

Input shaping works by splitting each sudden move into smaller, delayed pieces timed to the printer's resonant frequency. The vibration from the second piece lands out of phase with the first, so the two largely cancel. The Wikipedia example uses a 1 Hz resonance: a step applied as two half-size inputs, 0.5 seconds apart (half the resonant period), produces oscillations that cancel.

The firmware needs to know two things: the resonant frequency of each axis and, in some firmware, a damping ratio. Prusa's documentation lists a default damping ratio of 0.1, and Klipper's documentation assumes the same figure for its default. The frequency is found by printing a test model and measuring it, or by using an accelerometer.

Because the move is spread over a short window, the corners of the print get slightly smoothed. That is the main cost, and it is why the shaper type matters.

What are the input shaper types?

The shaper types differ in how much they smooth the motion and how forgiving they are of a wrong frequency. Klipper's documentation orders the smoothing as ZV < MZV < ZVD ≈ EI < 2HUMP_EI < 3HUMP_EI, and it gives each a duration in terms of the shaper frequency.

Prusa's M593 command exposes six types by number: ZV (the default), ZVD, MZV, EI, 2HUMP_EI and 3HUMP_EI. As a rule, pick the one with the least smoothing that still removes the ringing, and treat the heavier shapers as a last resort.

How do you set up input shaping?

You set up input shaping by finding each axis's resonant frequency and entering it, with a shaper type, in firmware. Support and method depend on the printer:

• Klipper: print a ringing test tower and measure the oscillations, or use an accelerometer for automatic measurement. Klipper's documentation notes the accelerometer route requires some crimping and soldering. Its worked example counts 6 oscillations over 12.14 mm at 100 mm/s, which gives about 49.4 Hz. See what Klipper is for background.
• Marlin: input shaping sits on top of Fixed-Time Motion, which Marlin says requires a 32-bit board with enough RAM. The documentation names only the ZV shaper.
• Prusa: the CORE One, MK4S, MK3.9S, MK3.5S, XL and MINI are supported, with firmware 5.0.0 or later on the MK4 family and 5.1.0 or later on the MINI/+ and XL. The CORE One L and XL have an integrated accelerometer and are pre-calibrated at the factory. See the Prusa CORE One first look.
• OrcaSlicer: its calibration menu includes an input shaping test for Marlin, RepRap and Klipper. The default frequency range is 15 to 110 Hz, and a damping value of 0.1 to 0.2 is a common start. See the OrcaSlicer beginner guide.

Some printers measure this for you, so check your maker's documentation before tuning by hand. Our broader printer calibration guide shows where this step fits.

Does input shaping make prints faster?

Input shaping does not speed up prints by itself, but it allows higher acceleration before ringing becomes visible. Klipper's documentation says input shaping has essentially no direct effect on print time; the maximum acceleration setting does. Prusa says the feature allows higher travel speed and acceleration, which reduces stringing and permits faster printing, with Pressure Advance handling the extra nozzle pressure.

Klipper recommends choosing the maximum acceleration as the lower of two limits: where ringing is still acceptable, and where smoothing starts to round small features. Its example found a small test gap widening from 3500 mm/s2, so it set 3000 mm/s2. It also says to keep square corner velocity at the default 5 mm/s, because raising it increases smoothing. For the extrusion side of fast printing, read what pressure advance is, and for the wider trade-off see print speed versus quality.

What can input shaping not fix?

Input shaping cannot fix a mechanical problem. Klipper's documentation says ringing often has mechanical causes such as a weak frame, loose or springy belts, misalignment or heavy moving mass, and that these should be fixed first. It also says ringing below roughly 20 to 25 Hz suggests stiffening the printer or reducing moving mass before tuning.

Other limits to know:

• Re-measure after changes. Resonances shift when moving mass, belt tension or the bed change. OrcaSlicer recommends recalibrating about once a year or after mechanical changes. Prusa recommends recalibrating after hardware modifications.
• Crash detection. Prusa says its crash detection is not compatible with Input Shaper because of the high accelerations and speeds.
• Filament still limits you. Prusa notes that wrong temperature or cooling can cause poor layer bonding at higher speeds.
• Z axis. Klipper says most users will not see direct quality gains from a Z shaper.

Frame design also matters, which is part of the CoreXY versus bed slinger comparison.

Sources

Figures come from Klipper's Resonance Compensation documentation, Marlin's Fixed-Time Motion page, the OrcaSlicer input shaping calibration wiki, the Prusa Knowledge Base Input Shaper article and the Wikipedia article on input shaping. Check your own firmware version, because options and defaults change.