Given that the rated lifetime is 50,000 hours at 40⁰C, how long is this fan realistically expected to survive in a chamber that runs at around 65⁰C most of the time?
If you do a search for bearing life vs temperature the big stroke results say the bearing life is cut in half for each 15C increase in temperature as a rule of thumb. May or may not be completely applicable to your fan but you’re up almost two of those increases so lifetime could be about 1/4 of 50,000 hours give or take - about 12,500 hours.
But articles also mentioned key events like some lubricants vaporizing out which could be step functions in how lifetimes are affected. So there could also be “gotchas” that dramatically shorten the bearing lifetimes beyond just what temperature itself causes.
But my current fan didn’t last anywhere near that long. I also suspect the lifespan drops off more quickly once you get close to the upper limit of its rated specifications. Even though I printed non-stop for a week during the last job, that still shouldn’t have killed the fan this fast.
I’ll track the lifetime of the new one as soon as I’ve replaced the faulty fan, probably tomorrow.
No, not really. Re-lubing the bearings with PTFE oil might delay failure a bit, but it won’t save a 40 °C-rated fan in a 65 °C chamber – and given where this fan is located, you really don’t want to be doing routine maintenance on it anyway.
I didnt read it. Im lazy and 3% phone battery. I wonder if the magnets slowly lose magnetism from the heat, or the bearing fails. Either way, that sucks.
Ah. You didn’t say that 40C was a max temperature rating. It could be 65C crosses one or more limits either for lubrication, materials, or even electronics ratings. You may need to look into shafted fans where motor and bearings are outside the heated region, or something similar where whatever motors you are working with can survive longer.
It could just be that 40c is what they tested it at and it would be that length of time testing at higher and lower temps. Seems like a potentially exaggerated time no mater what, that = 5.7 years I believe? Could be wrong, I’m pretty good with math except when it involves numbers…
you should do no such thing, the fan bearings have their factory lube. You may in fact reduce the lifespan by introducing the wrong stuff (actually very likely).
L0rd, I’m going to assume based from experience that the 65C lifespan will be less than the 40C rating, maybe somewhere around 30-40% reduced, but there will be other variables too, like the ingress of plastic particulate/fumes.
Even if it were halved to 25k hours, that’s a lot of print time… (edited to remove references to optional add-on fans)
Not trying to argue. I was interested, so did a little search. Ptfe oil seems to be commonly used for bearings that get hot. Or ptfe grease. The grease would be harder to get into the bearing though.
Warning: AI incoming. I did not type this.
“”“”“”“”“” Yes, PTFE (polytetrafluoroethylene) oil is good for bearings that get hot because PTFE’s high-temperature stability and low friction properties can protect them from wear. However, it’s crucial to use a specific PTFE-based grease or high-temperature oil formulated for the specific operating conditions, especially if the heat is extreme. For very high temperatures, synthetic oils with PTFE additives are recommended to prevent failure and provide superior lubrication.
Benefits of PTFE for hot bearings
High-temperature stability: PTFE itself can withstand high temperatures, with many products designed to operate effectively in temperatures up to
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or even
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.
Low friction: PTFE has an exceptionally low coefficient of friction, which reduces resistance and wear on bearing surfaces.
Chemical inertness: PTFE is resistant to many chemicals, making it suitable for harsh environments.
Reduced need for reapplication: Some formulations can act as a self-lubricant, providing a continuous lubricating layer that reduces the need for frequent reapplication.“”“”“:”:“”“”"
The only reason I thought of it, is because I already use it on bearings. Just not on a fan motor yet
For a high speed bearing that gets hot, acer racing sin oil works great. Its ptfe based.
Im just not sure why so many bearing manufacturers either make their own versions or suggest it. For high temp situations. Been doing alot of reading, and it seems legit. Almost everywhere, specifically suggest synthetic ptfe based oil
Dunno, if a manufacturer suggests it for some particular bearing I’d use what they suggest. But I wouldn’t generalize that observation to other bearings just because they get hot.
This isn’t my field, really all I know about bearings is that you want them to roll and not slide, so in the absence of specific advice to the contrary I avoid additive oils in roller bearings and linear guides.
In linear guides I don’t want to grease I use Mobil SHC 625.
