Print fan speed override



  • I would like an additional parameter to the M106 code that can be issued during a print to set a "PWM offset" to following fan speed requests.

    Example:
    Fan setup with M106 P0 L0.15 X1.0
    I issue M106 P0 Y0.4
    a following M106 P0 S0.3 will result in 70% PWM
    and a M106 P0 S0.8 will result in 100% PWM
    The I issue a M106 P0 Y-0.4
    a following M106 P0 S0.3 will result in 15% PWM

    The use case is to be able to increase or decrase fan speed during a print without having the speed reset next layer change/bridging operation. It happens quite often that i notice during print that I created the gcode-file with to little och to much cooling.

    Then there would of course be nice with an interface for this in DWC, but not necessary.


  • administrators

    The real problem is that the slicer generates commands to set the fan PWM. It would be better if it generated a command to tell the firmware what type of move was coming up, then you could set up the print fan speeds you want for each type of move (first layer, other layers, bridging etc.) and change sem separately on-the-fly. We're having discussions with the authors of a slicer about doing this. Once we have agreed a specification with them and any other interested parties, we will publish it; then I hope that other slicer suppliers will make the same facility available.



  • Sounds even better! Then it could be set up in the filament load macro to run the fan different on different printers with the same filament profile in the slicer.

    Something similar for hotend and bed temperature would be super as well. Right now I need to have one filament profile in my slicer for each printer due to different temperature needs. It would be cool to be able to override those temperatures as well with a gcode that I can put in my filament load macro.


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