Strange failure rate of fans



  • Hi, I appear to be getting through fans, both hotend and part on a regular basis. They seem to present the same fault, at first they run absolutely fine, but after a few months then they don't start up on their own, but if you manual flick the blades then they start spinning properly. after a while though they just wig out completely.

    Now I may just be buying bad fans, but I have experienced this phenomena 4 times in four months with both axial and radial fans. Everything runs at 24V. Do I have the correct settings?

    ; Fans
    M106 P0 S1 I0 F500 H1 T45 ; Set fan 0 value, Extruder 1 Fan. PWM signal inversion and frequency. Thermostatic control is turned on
    M106 P1 S0 I0 F500 H-1 ; Set fan 1 value, Extruder 1 Part Fan. PWM signal inversion and frequency. Thermostatic control is turned off
    M106 P3 S1 I0 F500 H2 T45 ; Set fan 1 value, Extruder 2 Fan. PWM signal inversion and frequency. Thermostatic control is turned on
    M106 P7 S0 I0 F500 H-1 ; Set fan 2 value, Extruder 2 Part Fan.PWM signal inversion and frequency. Thermostatic control is turned off


  • administrators

    Those fan settings look OK to me. 500Hz may be too fast a PWM frequency for some fans, but it should not affect the fully-on behaviour.

    I suspect the problem is caused by the type of fan you are using. When I converted my delta to 24V a few years ago, I used three 40mm 24V fans sourced from a UK supplier. After a few weeks of use they became noisy. So I replaced them with ball bearing fans (the originals had sleeve bearings) bought from a Chinese supplier vie eBay. They are still running well today.



  • Do you have the specs of the fans? Do they come with a MTBF rating? Personally, I'm a bit of a fan nut. I can't stand loud fans and I can't abide by fans that might just up and die on me, so I always buy quality fans from reliable places. Cheapo fans will die, and if they are of the same make and model, they will likely all fall to the same fate.

    I have switched entirely to Sunon or Noctua fans. Accept no substitute. I've never had one of these brands fail on me.



  • cheap fans, like almost everything else, are cheap for a reason...



  • I did once cave and buy a 3 pack of blower fans from amazon for 5$ free shipping. The first fan I hooked up had a loud pop sound and an awful awful smell. It released the blue smoke. I took it off and peeled back the sticker. And underneath I saw that the black wire was connected to the terminal screen printed with a plus sign and the red wire was connected to the terminal screen printed with the minus sign. I figured out why they were so cheap. I checked the other fans, same thing. I wired another one up again, this time with wires reversed, and it worked. It was loud, but it worked. I immediately went to digi-key and ordered a sunon blower. Luckily it didn't kill the board.



  • I suggest buying some Sunon fans, they even have some 5015 blower fan like MF50151VX-A99, they are not the quiets but super powerful. If it it is too loud you can easily run it at lower PWM and they still will coll even PLA fine.



  • Thanks to everyone for their comments, so, and let me take a moment to reflect here, but yes, you are all accusing me of being a cheapskate 🙂

    I can't use Noctua as they don't do 24V 40mm axial or 40mm
    blower and Sunon don't do any small blowers.

    Any other suggestions?

    Here's the one I have at the moment
    0_1558076099453_fan.jpg

    dc42: you say 500Hz may be a bit fast. what would be the standard setting?

    Thanks


  • administrators

    @pcsentinel said in Strange failure rate of fans:

    dc42: you say 500Hz may be a bit fast. what would be the standard setting?

    The blower fans I have tried don't like PWM at all. They sort of work at very low PWM frequencies e.g. 10Hz.



  • @pcsentinel said in Strange failure rate of fans:

    Thanks to everyone for their comments, so, and let me take a moment to reflect here, but yes, you are all accusing me of being a cheapskate 🙂

    I can't use Noctua as they don't do 24V 40mm axial or 40mm
    blower and Sunon don't do any small blowers.

    Any other suggestions?

    Here's the one I have at the moment
    0_1558076099453_fan.jpg

    dc42: you say 500Hz may be a bit fast. what would be the standard setting?

    Thanks

    Just search the web for "24V radial"!

    I remember from my buildup that these companys could have radial-blowers with 24Vdc, but some of them a little bigger then 40mm, maybe 50 or so (you could put a 24vdc-12vdc dcdc-converter to use 12Vdc fans also?):

    • sunon
    • ebmpapst
    • minebea
    • sepa
    • wallair
    • panasonic
      ... search the web for "ONE-OF-THE-ABOVE-LISTED-VENDOR fan alternative"

    Most big electronic-stuff-vendors have really nice websites nowadays where you can just navigate to your product-category, then input your constrains, and it throws back what is left, companies like:

    • distrelec
    • conrad
    • rs-components
    • digikey
    • mouser
    • farnell
    • Newark
    • element14
      ... search the web for "ONE-OF-THE-ABOVE-LISTED-VENDOR alternative"

    The web might throw up a hundred more companies/vendors! Good luck! Of course you can always with a little risk "gamble"-buy on alibaba, ebay, etc. Most of the stuff just runs fine...

    Also you can always make a small circuit where you address the problems with some components to cancel it out, that written here, I am not good at it 🙂

    EDIT: Sorry for the long post. And yes, I am also using cheap components, they might not come with a 100%-part check, but are budget-friendly 🙂



  • @pcsentinel said in Strange failure rate of fans:

    I can't use Noctua as they don't do 24V 40mm axial or 40mm
    blower and Sunon don't do any small blowers.

    Just get a step down converter and connect it + output to the middle pin of V_FAN select jumper.
    This is really the best solutions since they are much more 12V fans then 24V.



  • I really like Delta BFB series. If you can use 12V motors it's a really solid option and pretty quiet at a given flow rating. They have a lot of options to choose from, sometimes as many as five flow rate (RPM) choices for a given package size.



  • @pcsentinel

    EDITEDIT-idea: Maybe increase the 100% startup-time to 5seconds or so to blow out any dust?

    Maybe dust and or heat (too close to the extruder?) kill your fans?

    I consider myself as lucky, that I could print parts at the local university out of high-temperature-PolyCarbonat on an Ultimaker-3 with which I printed "frames/hinges" with which I could "decouple" the fans thermically from the metal-hotends and other stuff to decrease the risk of a shorted life of those fans because of thermal stress. Having a strong 100% blow when "firing up" the duet2 helps keep the dust out.



  • Getting stiff and hard to start but not getting noisy does sound to me like contamination. I've noticed my hotend fan would really like to suck in any stray hair of filament hanging around the bed area. I expect dust will get in as well. Dust seems to be what usually kills fans in electronic devices. If they don't choke, then they may make it all the way to rattling old age.


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