UM3 print head fan disabled?

[chhu79 0]

Hi,

I noticed recently on a print (PLA & breakaway) that the print head cooling fan (front) is not spinning. At first I thought it is clearly broken, but I realized later that it shortly spins fine after power-on. The print also looks fine, and now I am wondering if it was disabled in the last firmware update or if something else is wrong. Unfortunately I cannot test it from the menues (only side fans) and the log is clean. Does the firmware recognize a broken front-fan? I tried also pushing the temps of both extruders manually to 255C but still not spinning...

I am worrying that the spreaded heat damages some electronics.

Thanks,
C

[Smithy 1,135]

Normally you get a lot of problems if the front fan is not working. The fan cools the upper part of the print head and the fan start automatically if the print core temperature is higher than 40° or 45°. Usually some plastic blocks the fan if it is not working, so check again if there is anything around the fan.

[fbrc8-erin 267]

The most common reason for the front fan to fail is usually that little hairs of filament get wrapped around it. You can clear these out with a pair of tweezers; if it hasn't been stuck too long it should run again once the hairs are removed. If it's spent too long trying to run but unable to, the motor on the fan itself will be burnt out and the fan will need to be replaced.

[chhu79 0]

Hmm odd. I was thinking about hairy stuff as it ran almost 1 year continuously, and there was / is a lot of dust. Got rid of most of it, but what strikes me is that the fan seems to run fine for a second after switch-on. Later dead... Looks like a case for warranty.

 

Thanks,

Christian

[kmanstudios 1,120]

Nope, that is normal activity. I run into it when I superheat my filaments during certain ops and get a lot of hairy stuff. Fan mobility = friction. Friction = heated strands of filament. Heated strands = expansion and general gooiness and then bog down to stop.

 

When not running ( turned on an generating heat) fibres shrink, releasing the fan until it heats up again.