Input Shaping How to Optimize For Better Prints

Input Shaping: How to Optimize for Better 3D Prints

Input shaping is a game-changing firmware feature for 3D printers that eliminates one of the most common print quality issues: ringing (also called ghosting). This vibration-induced artifact appears as repeating, faint copies of sharp edges on your prints, caused by the printer's motion system oscillating after rapid direction changes. Optimizing input shaping lets you print faster with sharper details, smoother surfaces, and less wear on your printer's components.

What You Need Before Calibrating

Before starting the optimization process, confirm you have the following:

• Firmware with input shaping support: Klipper (native support), Marlin 2.4+, RepRapFirmware 3.3+, Prusa Firmware 3.10+, or Bambu Lab firmware (built-in).
• An accelerometer (recommended for Klipper and Marlin users, as it automates resonance measurement).
• A ringing tower test STL (available from Klipper documentation or Thingiverse).
• Calipers or a ruler for manual calibration.
• Basic knowledge of your printer's firmware configuration.

Step-by-Step Input Shaping Optimization

1. Confirm Firmware Compatibility

First, verify your printer's firmware supports input shaping. Klipper and Bambu Lab printers have native, easy-to-use input shaping tools. For Marlin 2.4+ users, you will need to enable the feature in Configuration.h before compiling and flashing firmware. If you use a pre-compiled firmware, check the manufacturer's documentation to confirm support.

2. Prepare Your Test Print

Slice your ringing tower with these settings to get accurate calibration results:

• Disable slicer-based acceleration control (let the firmware manage acceleration).
• 0.2mm layer height, 2-3 perimeters, no infill, 60mm/s print speed.
• 100% part cooling fan, 0.4mm nozzle (default for most users).

Print a baseline tower with input shaping disabled first, so you can compare results after calibration.

3. Measure Resonance Frequencies (Accelerometer Method)

This method is fastest and most accurate, especially for Klipper users:

• Mount the accelerometer to your printer's toolhead (and bed, if calibrating dual axes).
• Run the RESONANCE_TEST command for the X axis, then repeat for the Y axis.
• Your firmware will output a recommended shaper type (MZV, ZV, EI, 2HUMP_EI, or 3P) and optimal frequency for each axis.

Common shaper types: ZV works for simple single-peak resonance, MZV for dual peaks, EI/2HUMP_EI for wider resonance ranges.

4. Manual Calibration (No Accelerometer)

If you do not have an accelerometer, you can calibrate manually:

• Print a ringing tower with input shaping disabled, then print additional towers with shaper frequencies starting at 20Hz, incrementing by 5Hz up to 80Hz.
• Visually inspect each tower, or use calipers to measure the width of ringing artifacts below sharp edges.
• The frequency with the smallest (or no) ringing is your optimal value for that axis.

5. Apply Your Calibration Settings

Input your optimal shaper type and frequency into your firmware:

• Klipper: Add a [input_shaper] section to your printer.cfg file, with shaper_freq_x, shaper_freq_y, and shaper_type (or separate shaper_type_x and shaper_type_y for dual shapers).
• Marlin: Use the M593 G-code command: M593 X<freq> Y<freq> for separate axis frequencies, or M593 F<freq> for a single combined frequency. Save to EEPROM with M500.
• Prusa/Bambu Lab: Use the built-in input shaping calibration wizard in the printer's menu or companion software.

6. Validate and Fine-Tune

After applying settings, print a validation model like a Benchy or a calibration cube with sharp edges. Check for remaining ringing:

• If ringing is still present, adjust the frequency by ±2-3Hz and retest.
• Gradually increase acceleration settings until ringing reappears, then reduce acceleration by 10-15% for stable, high-quality prints.

Common Pitfalls to Avoid

• Calibrating only one axis: X and Y axes almost always have different resonance frequencies, so calibrate them separately.
• Over-damping: Using a shaper frequency that is too high will make print details look soft or blurry.
• Skipping recalibration after hardware changes: Adding dampers, a new extruder, or a different bed surface changes your printer's resonance profile. Recalibrate after any hardware mods.
• Using low-quality accelerometers: Cheap clone accelerometers can return inaccurate frequency readings, leading to poor calibration.

Advanced Optimization Tips

• Use separate shaper types for X and Y axes if their resonance profiles differ significantly.
• Combine input shaping with pressure advance: Input shaping handles motion vibrations, while pressure advance fixes extrusion-related artifacts for the best possible print quality.
• Test calibration with your most common print materials: Bed temperature and part cooling can slightly shift resonance frequencies for some printers.

Final Thoughts

Optimizing input shaping takes less than 30 minutes for most users, but delivers immediate, noticeable improvements to print quality. Make it a habit to recalibrate every time you modify your printer's hardware, and you will get faster, smoother, more detailed prints every time.