Print cooling fan behavior doesn't match G-code on A1 mini

user_102303967 · October 6, 2025, 8:16pm

But the Fan speed-up time feature doesn’t work well when printing with multiple materials

Fan speed not restored correctly with AMS or timelapse when "fan start early" option is enabled

opened 05:04PM - 27 Aug 25 UTC

bug

### Is there an existing issue for this problem? - [x] I have searched the exis…ting issues ### OrcaSlicer Version 2.3 ### Operating System (OS) Windows ### OS Version win 10 ### Additional system information _No response_ ### Printer a1 mini ### How to reproduce Enable "Fan start early" in print settings. Print a model with AMS (filament change) or enable timelapse recording. Observe that after filament change (or timelapse snapshot), the fan does not return to the expected speed. Check the generated G-code – sometimes the M106 command for fan start is inside a conditional block and does not appear in the final file. ### Actual results After AMS filament change or timelapse snapshot, the part cooling fan sometimes does not restart. The M106 command for fan speed is missing in the final G-code because it was wrapped in a conditional block and skipped. As a result, the fan stays off or runs at the wrong speed for the rest of the print. ### Expected results The part cooling fan should always start at the correct speed after AMS filament change or timelapse snapshot. The slicer should insert an unconditional M106 command both at the pre-start (early fan spin-up) and again at the actual fan start point, so the command is never skipped due to conditional blocks. ### Project file & Debug log uploads [Cube_fun_bug.zip](https://github.com/user-attachments/files/22010711/Cube_fun_bug.zip) ### Checklist of files to include - [ ] Log file - [ ] Project file ### Anything else? This issue seems to be the same as or closely related to previously reported bugs, which were closed without a proper fix: https://github.com/SoftFever/OrcaSlicer/issues/8796 https://github.com/SoftFever/OrcaSlicer/issues/9024 The problem is still reproducible in the latest OrcaSlicer release. I was able to work around the timelapse case by manually editing the settings and forcing the conditional block to be removed. However, this is only a workaround and does not fix the AMS filament change case. The issue still causes inconsistent cooling and potential print failures.