Hot-end fan stopping mid-print



  • Following on from a post about a Magnetic Filament Sensor Issue I raised here:

    https://forum.duet3d.com/topic/14018/no-angle-reported-by-magnetic-filament-sensor

    Problem:

    Hotend fan starts with the printer normally, continues to run normally while printing, but at random points fails mid-print and stops. Manually spinning the fins gets it going again but by this point, it's too late and plastic has melted above the melt zone and the filament cannot be extruded.

    This has not happened every time I've printed, I have managed to print a part for several hours without any issue, the print finishes perfectly, then 15 minutes into the next print, the fan stops.

    I've already dismantled and cleaned the entire hot-end using a hot air gun a number of times to unblock and am very hesitant to try it again

    I am running a Smart Effector with an official E3D V6

    I have already replaced the 30x30x10 24v fan with one from the E3D site and have even gone as far as to replace all connectors (as in, cut off old connectors, re-crimped and re-attached) The fan currently attached has it's original crimps from the factory.

    There are no other issues with the smart effector, the LED's stay lit, it's working superbly well in terms of calibration, I simply have the hot-end fan fail randomly mid-print.

    Can any recommend what I can check? The Smart effector is new, I had this issue the first time I used it but assumed it was down to my assembly, however, now I've iterated several times I'm not sure what else to do differently.

    Any help would be greatly appreciated!

    Thanks,

    Dave



  • I had this same problem, turned out that just the position of the fan in relation to the mag ends was causing it not to spin. If the face of the fan is rotated towards a pair of rod ends, try rotating it so the face is more parallel with one of the long sides of the effector.



  • @dave-poltorak

    Are you using magball arms? If so, how do you have them configured in terms of magnetic fields?
    On Haydn's arms, the typical installation is so the measurement stickers alternate i.e. if on one arm, the sticker is closest to the effector, the next arm, the sticker is closest to the frame and so on.

    E3D's fans are also known to not work brilliantly with PWM.
    Could you post the portion of your config which corresponds to the fans?



  • Thank you @jay_s_uk and @blt3dp for such quick response, think you are both on the mark here:

    I am indeed using Hayden Magball arms

    Currently, the stickers do not alternate, I thought I had assembled them with alternating poles going round but I paid no attention to the stickers.

    Also, the fan is facing more towards a set of magballs (short edge) more than it is the long edge. The only issue with this is the cooling fan assembly that I've chosen, I cannot rotate the hot-end fan any more with it attached.

    Pictures of current set up before I change:

    20200128_193258.jpg 20200128_193312.jpg

    With respect to config, I don't believe I have anything for the hot-end fan as it's the always on fan?

    I will clean the blockage and then re-assemble with the stickers alternating. I am also printing PETG next so I won't need the cooling fan, I'll leave it off and look for a re-designed version that does not need the hot-end fan to be rotated.

    Thanks

    Dave



  • @dave-poltorak
    For the config, you can vary the frequency that is used for the PWM. I use 500hz with my E3D fan and haven't had an issue. I'm not sure what the default is if it's not set.


  • Moderator

    @jay_s_uk said in Hot-end fan stopping mid-print:

    @dave-poltorak
    For the config, you can vary the frequency that is used for the PWM. I use 500hz with my E3D fan and haven't had an issue. I'm not sure what the default is if it's not set.

    If he's using an always on fan port there wouldn't be a PWM frequency at all? At any rate I believe the default is either 200 or 500hz



  • Just a quick note to say that the fan has had no issues once rotated away from the Magnetic Balls.

    I also have to say I'm a big fan of the Magentic filament sensor, its readings are really helping me understand if the printer is well calibrated all around (including extruder and hotend distance)

    Thanks for the help all.

    Dave


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