Problem: Cooling fan behavior does not match G-code or preview — turns off too early on overhangs
Firmware Version: 01.04.00.00
Printer: Bambu Lab A1 mini
Steps to reproduce:
- Slice a PETG model with OrcaSlicer 2.3 or Bambu Studio 2.0.2.57
- Enable 100% fan for overhangs in slicer settings
- Optionally enable/disable “start fan early” setting and re-slice
- Begin printing and observe fan behavior during overhang sections
- Notice that the fan either:
- turns off too early (before or at the start of an overhang), or
- turns on briefly but immediately reverts to previous speed,
- or never activates on overhangs as expected
Other information:
- Behavior reproduced with PETG and default slicer profiles
- Issue affects narrow overhangs more noticeably
- May also affect bridge cooling — observed early fan shutdown
- Likely not limited to A1 mini and may affect other models
Related thread: Main discussion thread here