Resonance at a certain speed  

RE: Resonance at a certain speed

Mine did the same, it seems that not everybody is as sensitive as us regarding those resonance noises.

I hope Phase stepping will solve this.

RE: Resonance at a certain speed

I uploaded a video but it does not show up!

you say "Mine did the same" as in: it does not any more? What did you do?

Mine is loud as a small train whistle. So I hope that Phase stepping will help as well cuz I am reluctant to print at nights as it sounds so bad!

Further analysis makes it clear that it is when printing perimeter at 80 mm/s. I will try to lower it to 75 mm/s tomorrow and se if I can use that as a workaround in the meantime.

RE: Resonance at a certain speed

Hi  Illerian, 

when you add the video, somehow you managed to include some formatting data, which stopped the video link being displayed. 

I removed the formatting, and now your video  link displays. 

the red bits show the problematic formatting

 
regards Joan

RE: Resonance at a certain speed

Hi @illerian, having listened to the video now, I can say that my Core One definitely does not exhibit such resonances. It's not just different individual sensitivity to resonant sounds as Scott suggested. In my printer, the chamber fans are the loudest when I print PLA in structural mode (i.e. relatively slowly), and the Y bearings and motors become the most audible contributors in Speed mode. But no resonance from other parts of the mechanism or frame.

Have you tried touching (lightly) various panels and CoreXY parts while the noise occurs, to dampen them and identify the source of the resonance? If you can pinpoint the source, it should be possible to tighten things down or add local damping, to suppress the resonances.

Caveat: Maybe there is also an influence from different motor tolerances, with some motors moving through their microstep pattern more roughly than others. If that should be the root cause of the noise differences which we observe between different printers, we will probably have to wait for Prusa's "calibrated phase stepping" firmware release, which should enable smoother motor movement in all units. 

RE: Resonance at a certain speed

Posted by: @illerian

you say "Mine did the same" as in: it does not any more? What did you do?

Mine is loud as a small train whistle. So I hope that Phase stepping will help as well cuz I am reluctant to print at nights as it sounds so bad!

Further analysis makes it clear that it is when printing perimeter at 80 mm/s. I will try to lower it to 75 mm/s tomorrow and se if I can use that as a workaround in the meantime.

Mine did that at 40mm/s and 80mm/s in straight X or Y direction too.

I write "did" because I sent it back because of that and really bad VFA/belt ripples. I just ordered a CORE One kit few hours ago.

RE: Resonance at a certain speed

Thank you @joanTabb, perhaps it is due to me using Brave browser?!

Mine is from a kit. I have torqued everything according to standard specs, except for metal screws fitted in plastic, due to unknown properties of said plastic so I am not sure what could be tightened more. I have it down to +/-0.01 Nm difference from standard, specially on linear rail mounting for instance. 

I have tried pushing lightly and pulling lightly where I can reach but nothing I tried have damped the resonance. The only steel plate I have not tried is the bottom one. I will try that tomorrow (well it is today now) as well.

I also get artifacts at around that speed as seen in this picture. I am sure I can calculate the exact frequency from the measurements off the Benchy. But that does not explain why it stops all of a sudden so I am not 100 % sure it is the resonance, and I might have a second problem 😕 .

RE: Resonance at a certain speed

I also use Brave Browser. 
so it's unlikely to be the cause directly. 

I think it's to do with the way you insert links and images. 

I Simply drag them into the bottom of the text input box, and when the screen colour changes  to Blue I Drop the link or file

regards Joan

RE: Resonance at a certain speed

Posted by: @illerian

also get artifacts at around that speed as seen in this picture. I am sure I can calculate the exact frequency from the measurements off the Benchy. But that does not explain why it stops all of a sudden so I am not 100 % sure it is the resonance, and I might have a second problem 😕 .

For surfaces oriented in the X or Y direction, you will probably find that these artifacts have a spatial period of 2 mm. It seems that (unfortunately) all Core Ones produce them, to varying degrees. They disappear at high printing speeds for many users. The ripple even shows up in printers which do not exhibit resonant acoustic noise.

The ripples are widely assumed to be related to the belt teeth, but there is no clear cause/effect relationship or fix so far. You will find one at least one long thread on "VFAs" here on the forum which discusses them. 

RE: Resonance at a certain speed

My suspicion is that it's down to different motor characteristics, as Jürgen suggested.  I have seen similar on my Mk4S.  I have a kit-built MK4 that has always been super smooth, but I have a MK4S that started life as a MK3S+, which was close, but not quite as quiet.  At one time I tried a set of motors that I bought elsewhere, and even within that set their smoothness varied if I just turned the motor spindles by hand.  The ones I bought from Prusa were fine (they were the 0.9 degree z-motors though, so no effect on x- or y-motion).  I recall that Prusa used to say that their motors were all individually checked - not sure where or when I read that, a blog post I think - and I assume that they simply rejected those with rough characteristics.  Is it possible that this is no longer the case, and that they expect that the motor variations will disappear when phase stepping arrives?

My CORE One also has super smooth motors, and from what I've seen it seems like it has VFAs that are at least at the low end of the scale.  So if phase stepping can indeed make the motors a bit smoother it seems like VFAs could well improve at the same time.

RE: Resonance at a certain speed

My Core One also has no resonance at all.
The only annoying noise after a while was a click when changing direction.
After I lubricated the linear rails, this also disappeared.

But I also had a similar resonance with my MK4S.
In the end, the cover of the lower bearing was a bit loose.

I would create a cube with an edge length of 150mm in the Prusa Slicer.
Then slice in vase mode and maybe 50mm/s.
Then increase the speed when printing until you have the maximum resonance.

Then you have enough time to see if you can recognize a cause somewhere.
Where it is safe to do so, simply feel and press everywhere. Especially in the area of the gantry, bearings and idler pulleys.
With a bit of luck, something will happen if you find the right spot.

RE:

Posted by: @rainer-2

The only annoying noise after a while was a click when changing direction.
After I lubricated the linear rails, this also disappeared.

Ah, thank you for mentioning that. I was wondering whether I am seeing some premature wear on the X bearing in my unit. Seems like I can hear the balls in the ball bearing cage click; this only started after a few days of using the printer. I have only lubricated very sparingly so far, which has not made the clicks go away.

RE: Resonance at a certain speed

I used the Prusa lubrication set and followed the instructions for the XL.

RE: Resonance at a certain speed

After more tinkering and testing * PI I conclude that it is around 80 mm, setting speed for perimeter, not external perimeter to 73 mm or 90 mm removes that resonance by 90+ %.

Sadly no poking, prodding, pulling, or pressing on any part of the printer have resulted in any clue as to where the sound is emanating from. I am considering slapping something like this (pardon the hideous link):

Siless 80 mil (2mm) 36 sqft (3.4 sqm) Car Sound Deadening mat

on the underside of the printer and hope for the best...  😀 

Nothing I have done, print parameter wise, have removed the ripples. So I conclude that it has nothing to do with the resonance, and happily refers that to the appropriate thread on this forum. 

RE: Resonance at a certain speed

Posted by: @illerian

Thank you @joanTabb, perhaps it is due to me using Brave browser?!

Mine is from a kit. I have torqued everything according to standard specs, except for metal screws fitted in plastic, due to unknown properties of said plastic so I am not sure what could be tightened more. I have it down to +/-0.01 Nm difference from standard, specially on linear rail mounting for instance. 

I have tried pushing lightly and pulling lightly where I can reach but nothing I tried have damped the resonance. The only steel plate I have not tried is the bottom one. I will try that tomorrow (well it is today now) as well.

I also get artifacts at around that speed as seen in this picture. I am sure I can calculate the exact frequency from the measurements off the Benchy. But that does not explain why it stops all of a sudden so I am not 100 % sure it is the resonance, and I might have a second problem 😕 .

I have found the solution to this as well. I ordered the accelerometer and ran an input shaping calibration and lo and behold, all the waves just went away!

RE: Resonance at a certain speed

Posted by: @jurgen-7

Posted by: @rainer-2

The only annoying noise after a while was a click when changing direction.
After I lubricated the linear rails, this also disappeared.

Ah, thank you for mentioning that. I was wondering whether I am seeing some premature wear on the X bearing in my unit. Seems like I can hear the balls in the ball bearing cage click; this only started after a few days of using the printer. I have only lubricated very sparingly so far, which has not made the clicks go away.

Ive got this as well.  I need to get the prusa lubrication kit tho.  Only the best for my girl.

I don't think it is mechanical.  It almost sounds like a bubble popping.  I'm wondering if it is the oil that is on it forming a seal as it passes over the bolt holes of the rail that pops.  It's just the way it sounds and the number of clicks it makes relative to the distance travelled.  Think more grease takes it out of the viscosity sweet spot that let's the bubbles audibly.

RE: Resonance at a certain speed

My Core makes the same noises, annoying, support informed, video sent, it should be fixed by firmware, I should be patient.4weeks later......:!!What are you talking about, we don't know what you're talking about, oh you ordered through a supplier, please contact the supplier regarding the warranty, we are not responsible for you, we have nothing more to do with the device. that's what I call super support. Thank you very much for the super printer and for the super help Prusa, the printer looks good and clanks cool when printing like an old Marlin.

A friend has the same problem, the device was exchanged for a new one after checking the rattling, it will arrive in a few days and we are curious to see if the rattling has gone.

Only I will be stuck with my 1350EUR scrap as Prusa is refusing me the guarantee.

I am still waiting for a reply email from Prusa, as well as the return label for the non-functioning Buddy Cam.

Fortunately, the printer looks good.

RE: Resonance at a certain speed

Did this accelerometer calibration help you to get rid of VFAs? To me, that boat side looks like VFA. Could you try to print some of these VFA test models? Thank you.

RE:

Mine makes that noise as well its really grating to me.  As confirmed above it seems to be at the 80mm/s speed this happens.  I also found if I push in on the metal side panels it mitigates it a great deal so I guess that is causing them to vibrate?  I may just change the profiles to avoid that speed or try some thin rubber inserts on the panel connection points.