If you've noticed "ghosting" or "ringing" near the sharp corners of your 3D prints, you are likely dealing with overshoot errors. These artifacts occur when the printer's print head carries too much momentum, causing it to vibrate after a sudden change in direction.
Understanding the Root Cause
Overshoot is fundamentally a physics problem. Most firmware settings are tuned for speed, but high-speed directional changes without proper acceleration management lead to mechanical resonance. To fix this, we don't always need new hardware; sometimes, a few G-code tweaks are all it takes.
Key G-Code Tweaks to Fix Overshoot
1. Adjusting Acceleration (M204)
The default acceleration might be too aggressive for your printer's frame. You can limit it directly in your start G-code or per-feature in your slicer.
M204 P500 ; Set printing acceleration to 500mm/s²
2. Fine-Tuning Junction Deviation or Jerk (M205)
Jerk (in Marlin) or Junction Deviation (in Klipper/newer Marlin) controls how fast the printer transitions between two lines. Lowering these values reduces the "snap" at corners.
M205 X8 Y8 ; Set Jerk for X and Y axes to 8
3. Pressure Advance / Linear Advance (M900)
If the overshoot looks like a bulge at the corner, it’s often due to internal nozzle pressure. Enabling Linear Advance allows the printer to decouple extrusion speed from motor speed.
M900 K0.05 ; Set Linear Advance K-factor
Conclusion
By implementing these G-code optimization techniques, you can significantly improve surface finish and dimensional accuracy. Start by lowering your acceleration by 20% and observe the results. Quality often requires a balance between speed and stability.
3D Printing, G-Code, Troubleshooting, CNC, Firmware, Print Quality, DIY
