Print cooling fan not coming on



  • I am able to turn the print cooling fan on manually in the DWC, but its not turning on by itself at layer 3 like it should. I'm reinstalling my slicer now. is there anything the Firmware that could contribute to this? should I reinstall it if reinstalling my slicer doesn't do the trick?The tech support from S3D just give canned answers that don't really fit the problem.



  • Some fans require a minimum voltage (PWM value) to start spinning. Sometimes, you can then lower the speed a bit afterwards, they just need a boost to get started spinning.

    EG, my print fans won't turn on below about 30% power.



  • this was working fine, now it hit or miss as to whether they will turn on or not.


  • administrators

    Here are some reasons why the print cooling fan might not be coming on:

    1. Bad connection in the wiring. It might be OK in some head positions and not ok in others.

    2. If the slicer is commanding the fan to turn on at less than full speed, you might need to change the PWM frequency. Lower frequency may help. Or you may need to use a longer blip time. Both of these are parameters in the M106 command. Some fans just don't like PWM.

    3. If your printer is a delta with magnetic arm joints, some fans don't work properly in the presence of the magnetic fields from the joints.



  • 1. all new wiring and I have already replaced the connectors
    2. I have the blip to full speed enabled, however I can still turn the fan on @ 3% manually in the DWC and it comes on. it doesn't even show that it should be on in the DWC, BOTH are at 0. its like it never got the command.
    3. CoreXY



  • If you can turn it "manually" through DWC then logic would dictate that the slicer isn't putting the M106 command in the file (or that it is putting M106 but with other parameters which prevent the fan from running). In your OP you state that the fan ought to come on at layer 3, so take a look at the gcode file and see if there is an M106 soon after the G1 Znnn (where nnn corresponds to the height for layer 3). If the M106 command is there, what comes after it? Full speed would be M106 S255.



  • G1 E-8.1000 F3000
    G1 Z1.469 F1800
    ; layer 3, Z = 0.469
    M106 S255
    G4 P500
    M106 S71
    M105



  • just an FYI does the same thing when I use Slic3r, will check out hardware tomorrow if time allows.


  • administrators

    Do those same commands (M106 S255, wait half a second, then M106 S71) work when you send them manually, with the same tool selected?



  • typing those into the G-code window does not get the fan to move, the fan slider still does


  • administrators

    @Cinpro:

    typing those into the G-code window does not get the fan to move, the fan slider still does

    Are you certain that you have a tool selected (type T by itself to check), and that the fan mapping for that tool is correct (type M563 P# to check, where # is the tool number)?



  • M563 P0
    Tool 0 - drives: 0; heaters (active/standby temps): 1 (0.0/0.0); xmap: X; ymap: Y; fans: 0; status: selected


  • administrators

    Which fan connector do you have the print cooling fan connected to? With that configuration, it should be fan 0.



  • I think I got it, it is mapped to fan 0, but I only had fan 2 available for PWM. I got a new board so I have have this one repaired (have to find someone, my hands shake too badly) when I swapped everything to the new board I put all the fans exactly where they were. so fan 0 got triggered, but since it wasn't there, no cooling fan. in future if I have a problem with a fan o can I map the firmware to tell it to use say fan 1 or fan 2? and one for the suggestion box, make the fans match in the firmware and the DWC having 0,1,2 and 1,2,3 is annoying.

    going to do a test print now to verify this, but the g-code you gave me earlier seems to work. thanks 😄


  • administrators

    If you add parameter F2 to your M563 P0 command, then fan 0 will be mapped to fan 2 when tool 0 is selected.



  • grr thats not it! 😞



  • M106 P0 S0 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
    M106 P1 S0 I0 F500 H-1 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off
    M106 P2 S0 I0 F255 H-1 ; Set fan 2 value, PWM signal inversion and frequency. Thermostatic control is turned off


  • administrators

    Which fan connector do you have your print cooling fan connected to at present?



  • fan0


 

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