3D printing can produce incredible results, but vibrations and resonance during printing can ruin your models. Klipper’s input shaper feature can help reduce vibrations for cleaner prints. This comprehensive guide will explain what input shapers are, how they work, and how to configure and tune them for optimum performance with Klipper.
What Is an Klipper Input Shaper and How Does It Work?
Input shapers are a firmware-level tool that modifies the motion commands sent to a 3D printer to counteract vibrations. The goal is to have the print head move in precisely the desired way without introducing new vibrations.
When a 3D printer changes directions or speeds, it exerts forces against the frame and bed. This introduces vibrations into the system at the natural resonance frequencies of the printer. Vibrations during printing cause inaccuracies and ringing artifacts.
An input shaper acts as a filter between the motion planner and motors. It monitors commanded motions and creates a tailored series of micro-delays to cancel out predicted vibrations. The delays are timed to interact destructively with the printer’s resonance modes.
This allows the print head to follow the intended toolpath more smoothly without exciting resonant frequencies. Input shapers dramatically reduce vibrations compared to unfiltered motion commands.
Different Input Shaper Types
Klipper offers three input shaper types – ZV, MZV, and EI. Each has advantages in certain situations:
- ZV (Zero Vibration) – Minimizes vibrations at a single resonance frequency. Simple but effective for prints with constant speeds.
- MZV (Minimal ZV) – Handles two distinct resonance frequencies well. Good general-purpose option.
- EI (Extra Insensitive) – Suppresses vibrations over a wide range of frequencies. Useful for variable speed prints.
Higher strength settings increase the input shaper’s effectiveness but reduce responsiveness. Start with lower strengths and tune from there.
Measuring Resonances
The first step in configuring an input shaper is identifying your printer’s resonance frequencies. Klipper has a dedicated resonance testing mode to measure this easily.
Here’s how to test for resonances:
- Home the printer and disable steppers.
- Set square_corner_velocity to 5 in the printer.cfg.
- Start resonance testing:
TEST_RESONANCES AXIS=X - Watch/listen for ringing and note frequencies.
- Repeat for Y axis.
Look for consistent frequencies between 15-150 Hz. Input those values into the input shaper configuration.
Configuring Klipper Input Shaping
Once you know your printer’s resonances, add an [input_shaper] section to your printer.cfg file:
[input_shaper]
shaper_type_x = mzv
shaper_freq_x = 58
shaper_type_y = zv
shaper_freq_y = 73
Set shaper_type to zv, mzv, or ei depending on your needs. Use your measured resonance frequencies for shaper_freq_x and shaper_freq_y.
Start with a shaper_type of mzv and strength of 50 for both axes. Tune strength higher or lower as needed.
Tuning and Tweaking Shapers
Input shapers require some fine-tuning to dial in. Here are tips:
- Try different shaper types and strengths to find the best balance.
- Re-test resonances after major printer modifications.
- Use higher strength values for problem materials like flexibles.
- Reduce strength if you see ghosting artifacts in prints.
- Use EI shapers for highly variable speed prints.
- Limit shaper frequency to 1/3 of the printing frequency.
Combining Input Shaping with Other Features
Input shapers work well with other Klipper vibration control options:
- Resonance compensation – Counteracts vibrations during prints based on accelerometer data. Use with input shaping for best results.
- Dual dampers – Having an accelerometer on both X and Y carriages improves vibration compensation.
- Linear advance – Adjusts extruder pressure to reduce ooze and ringing. Works alongside input shapers.
- Accel control – Limits acceleration/deceleration to avoid exciting resonances. Use conservative values.
Input Shaping for High Print Quality
Vibrations are the enemy of print quality. Even small oscillations can result in visible defects. Input shaping provides a way to combat those unwanted vibrations.
When properly tuned, Klipper’s input shapers minimize resonance excitations during prints. This results in smoother motion, sharper corners, and less ringing. Input shapers also allow faster printing speeds without quality loss.
Give input shaping a try to see substantially improved surface finish and accuracy. It’s an effective way to take your print quality to the next level.
