Belt Tensioning
Proper belt tension is crucial for the coreXY motion system. Loose belts or insufficient tension can cause many printing issues, such as circles being printed as ellipses.
The belts and gantry form a mass-spring system, where the belt acts as the spring (k) and the gantry as the mass (m). The system’s natural frequency is f = √(k/m). Loose belts lower both k and f, thereby affecting vibration compensation.
P2S monitors belt tension using this equation f = √(k/m). During calibration, the motor generates vibrations at different frequencies and looks for resonance, which occurs when the input frequency equals the natural frequency. We call this process a frequency sweep, which produces noticeable noise as the pitch rises.
When the natural frequency of the P2S changes, the belts need to be tightened. This can be done with a simple adjustment.
Video Guide
XY-Axis Belt Tensioning
- Before tensioning the belts, please turn off the printer and remove the top glass cover.
- Use an H2.0 hex key to slightly loosen (only 1–2 turns, do not remove the screws) the four tensioning screws to release the XY belts.
- Manually move the toolhead back and forth along the XY directions as widely as possible, 3–5 times.
- Retighten the four screws at the back of the printer.
Note: Do not overtighten the screws to avoid stripping the threads.
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Z-Axis Belt Tensioning
ℹ️ Note: In rare cases, the Z Belt may create a squeaking sound during movement. Applying a very small drop of oil to the contact point between the belt and the Z Belt Tensioner Idler can help reduce the noise. Use only a minimal amount. Excess lubrication may cause the Z Axis to operate incorrectly.
- Tilt the printer backward to expose the bottom belts and tensioner.
- Use an H2.0 screwdriver to loosen the tensioner screw. (No need to fully remove it.)
- Pull the Z-axis belt up and down 3–5 times.
- Then tighten the tensioner screw again to complete the Z-axis belt tensioning.
Calibration
- Reinstall the top glass cover and power on the printer.
- On the screen, tap “Calibration - Print Calibration,” check only Vibration Compensation, and complete the calibration.
- You can also enable this in Bambu Studio by clicking the option shown below: