Loud fan noise upon start up - is this normal?  

RE: Loud fan noise upon start up - is this normal?

I have had this on old fans, as they wear out, 
It is  often possible to unscrew the fan, partially remove the label in the centre of the back of the fan, add a little light oil, replace the label, and re fix the fan, then you will probably have a quiet life, whilst you order a replacement fan... the bearing will eventually wear out, but by that time you should be prepared with a spare fan. 

regards Joan

RE: Loud fan noise upon start up - is this normal?

Yes, this is normal. 

RE: Loud fan noise upon start up - is this normal?

Most cooling fans has sliding bronze bearings and they tend to dry out as Joan describes - the drop of thin sewing machine oil fixes the problem for a long time. Has been using that solution on worn out computer fans for over a decade.

RE: Loud fan noise upon start up - is this normal?

I have a bottle of singer sewing machine oil and a precision oiler which I use for the bearings and fan bearing.
I've done the fan 3 times in a year so far, and I apply a drop of oil onto the steel rods before every long print or before a few short prints, then wipe off the excess and dust from the ends of the rods where it collects.

RE: Loud fan noise upon start up - is this normal?

Thank you all - So just for reference this is a bran new unit. One post says it is "normal" - I will send to support and see what they say as well.

RE: Loud fan noise upon start up - is this normal?

It depends on the sound. If the "loud" noise is just the sound of rushing air it is normal as both fans are spun up to 100% briefly as part of the systems POST (Power On Self Test). Because nothing else is happening, it is likely that your room is very quiet at that point so it sounds louder than when printing. If you are convinced that the rushing air sound is louder than normal, check to make sure that the fan blades (on both fans) don't have an accumulation of dust on them.

But if the noise is something other than rushing air you may be having problems.

RE: Loud fan noise upon start up - is this normal?

OK thanks again all - here is a link to a video so you can hear the noise for yourselves:

RE: Loud fan noise upon start up - is this normal?

@mgtarallo

The fan spinning fast for a little while when you turn on or reset the printer is normal (that's what I meant when I said "this is normal" before).  The fan spins fast for about a second and then turns off. I think that's the printer's way to saying "I've been reset."

However, yours sounds like the fan may be scraping against something.  Do you get a similar "scraping" sound when the fan turns on during printing (if you just turn it on through the LCD settings menu)?  You may want to check if anything is blocking the fan blades.

RE: Loud fan noise upon start up - is this normal?

Just an update for all of those that stumble on this post - the noise occurred at high speed on startup test - prusa support told me to loosen the 4 screws around the fan - and that solved it. The housing must have been too tight.

RE: Loud fan noise upon start up - is this normal?

@mgtarallo

i have noise and have not yet found it, I may try that fix 

thanks for that

RE: Loud fan noise upon start up - is this normal?

@mgtarallo

Thanks for this tip! While I was unable to replicate the loud fan noise using M106 commands, loosening the screws a bit indeed made it much more tolerable.

-Lars

RE: Loud fan noise upon start up - is this normal?

Scratch that. On my next print, the fan was back to the normal noise level. It's only while doing the _second_ layer, though.

RE: Loud fan noise upon start up - is this normal?

Get back with support, this fan is supposed to be really quiet, it's supposed to be a premium part; therefore, if the machine is new then Prusa would have to replace it. That loud noise is not normal for a new fan. It does sound as if the blades are hitting against something. You can crank up the fans in the setting menu under temperature.

Phil

RE: Loud fan noise upon start up - is this normal?

 Thanks all - mine is back to doing the same noise again - i think the fan may need to be replaced. I will send this thread to support.

RE: Loud fan noise upon start up - is this normal?

I've started having the same issue recently. I contacted support, and quoted this thread and the linked video.

The official response I got is:

The noise upon start is because the fan will spin to the max RPM to check the continuity on the fan wires. The fan may be slightly noisier upon start, but the fans RPM's are driven by PWM reg. so since it's not noisy due printing, it's not an issue and you don't need new fan 🙂

As for the why it started suddenly, despite it not always being like that, this is what I got:

It can because the bearings in the fan may be stiffer as it were brand new.

Personally I'm fine with this as it's only on startup, and will not replace the fan for now.  The support explanation, both makes sense and it doesn't to me personally - since this started happening after owning the printer for about 2 months (not printing 24/7), and that seems a bit short amount of time to consider this normal noise due to fan wear.

RE: Loud fan noise upon start up - is this normal?

Hi,

I just re-reviewed your video and comparing it to my startup noises feel that your noise is like mine, not coming from the extruder fan but coming from the nozzle fan. I ended up with an error sometime after mine started making the noise and luckily had on hand a replacement. These aren't expensive items and are easily replaced. The next failure I plan to put an xh connector on the cable and fan to avoid, unnecessarily, tearing down the cabling.

RE: Loud fan noise upon start up - is this normal?

I got a new nozzle fan under warranty - Prusa agreed that it was not working as intended, esp. as it ran much quieter at 100%. The most likely explanation is that I lost a ball from the ball bearing. Due to other commitments (and as Phil says, the annoyance of tearing down the cabling) I have not replaced it yet, so I can tell if the replacement helped.

To check if it's just the normal startup sound, you can run the fan manually at 100% and compare.

-Lars

RE: Loud fan noise upon start up - is this normal?

Lars, 

I did the same thing, got one under warranty, eventually I got a fan error and replaced the unit. Like you've said it's annoying but not worth the teardown, but if the fan fails during a long print?

Good luck and keep safe. 

RE: Loud fan noise upon start up - is this normal?

I've decided to try and figure out why the inconsistencies in the support responses happen, so I asked more about that. Here's the final response:

Regarding issues with the fan, it is important to differentiate the problem with a noisy fan during print and the noise when you turn the printer on, as that is indeed normal and may appear later. 

The brand new fan might not behave like that as the moving parts have to "break-in". There might also be differences between individual fans. 

There might have been a few cases where our agents did not know about this behavior and mistakenly sent a replacement fan even though it is not needed. Since then we have covered this case in our weekly update and it should not happen again.