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FireHawk
(@firehawk)
Active Member
freshly assembled MK3 is super loud

Hello there!
I finished assembly of MK3 (part revision B7/R3), and I have to admit I was shocked by noise levels of this small machine. Everyone on the internet was praising MK3's low noise in Stealth mode, but I can hear printer working in Stealth mode in the next room behind 2 closed doors. I guess it's not normal, so I came here looking for advice or other kinds of help.
First of all, problem description:
Movements by X, Y and Z axis are very loud. The print fan is extremely loud and has a high pitch.
Steps I did so far to debug/fix the problem:

1. Took a looooong read of this forum.
2. Slightly unscrewed bolts of motor holders, tapered nuts, belt pulleys, moved components by hand, ensured alignment, tighten everything evenly, added lube to all rods. Loosing of tapered nuts had a small positive effect for Z-axis movement, everything else had no effect.
3. Detached LCD to check it was resonating. No, it was not.
4. Detached PSU to check it was resonating. Yes, it was resonating a bit. Added small shock-absorbers, it got better, but not perfect.
5. Put printer on the solid floor, to exclude the possibility of the resonating table. No effect.
6. Filament spools also were innocent and were not involved in the noise-making activity at all.
7. Removed heated bed and Y-carriage to debug noise on Y-axis. There were 2 sources of noise, obviously:
Motor - please look at this
Carriage - a weird one, initially I was pretty sure that bearing were sources of noise, but without heated bed and attached belt carriage is moving smoothly and quietly. With everything attached (but not connected to the motor) I hear loud metal clanking.
I tried re-attaching motor, re-tightening the belt, reassembling belt tensioner - no effect.
8. Changed tension on X-belt. No effect.
9. Completely re-assembled the printer, this time under the close supervision of my son. No effect at all.

As for another source of noise, print fan, I guess it's just defective. I made this video, and addressed this particular problem to support.

Any ideas are appreciated.

Posted : 05/02/2019 10:15 pm
RetireeJay
(@retireejay)
Reputable Member
Re: freshly assembled MK3 is super loud

I guess this is your first printer - and you have excellent hearing. 😀
The "click" sound of the knob is the only reference on the video to how loud the machine is overall, and your printer seems to have about the same ratio of loudness relative to the click as my machine does.
My previous machine (not a Prusa), on the other hand was significantly louder. So to me, this MK3 printer really is quiet. To be honest, when I walk out of the room, even with the door open, I cannot hear it. Our house has carpeted floors; maybe that has an influence on the transmission distance.

Posted : 05/02/2019 11:15 pm
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(@)
Illustrious Member
Re: freshly assembled MK3 is super loud

The printer sounds normal: the fan might be a bit noisy. Did you check inside the fan rotor for any artifacts like a piece of packing stuck inside the blades?

In stealth, the cooling fan is the loudest part of my printer. Centrifugal fans have a 40dB or so noise spec. That's pretty loud in a quiet room. For comparison, the average computer fan is under 30dB, or more than four times quieter; I have six fans in my computer under my desk, and combined they are about as noisy as my printer fan. The axis motors and movement noise is still audible in stealth, but the fan is what I hear across the room. In the next room around a couple of corners (bedroom) I can still hear the printer if the furnace isn't running. In Normal Mode, the motors screech above the fan noise, and the printer is easily heard in the next room; but I can sleep with it running full speed.

In practice, I can use the printer in normal mode while watching TV, but stealth is less distracting. The printer is on my kitchen table, 12 feet away from my TV chair.

ps: the video of the Y-Axis motor without belt is definitely not right. The motors are (should be) virtually silent when moving on their own.

Posted : 05/02/2019 11:25 pm
gnat
 gnat
(@gnat)
Noble Member
Re: freshly assembled MK3 is super loud

Like RetireeJay I'm using the button click for reference.

There is some whine going on until you turn off the fan and then it comes back after you turn it back on. That is not normal (or at least not like mine. Check that the fan is functioning properly and the blades aren't touching anything.

Otherwise (when the fan is off) it sounds just like mine does.

This is my first printer so and the only others I've been close to were in loud environments so I have no real reference, but I would call the MK3 quiet. I have hard wood floors throughout my house (so nothing absorbing sound), the printer is right by the door (which is almost never closed) of my office which is right at the bottom of the steps. My living room is at the top of the steps and I can only hear the printer if the TV is off and no one else is around making noise. I have yet to use the silent mode as I've not felt the need.

Additionally, I've worked multiple days in the office while the printer did it's thing about 3 feet behind me and it wasn't unbearable by any stretch.

MMU tips and troubleshooting
Posted : 05/02/2019 11:27 pm
Bunny Science
(@bunny-science)
Noble Member
Re: freshly assembled MK3 is super loud

That y-stepper sounds awfully loud to me. One way that motor can become MUCH louder than normal is the motor body rattling against the rear metal bracket. The plastic motor mount can sometimes position the motor in just the position to do that. A very thin piece of rubber foam between the motor body and metal bracket solves that problem.

Posted : 06/02/2019 4:00 am
FireHawk
(@firehawk)
Active Member
Topic starter answered:
Re: freshly assembled MK3 is super loud

Thanks a lot for your comments, guys. I checked recorded video with noisy fan, and I am quite surprised how it sounds - because indeed on video clicks are very loud. Maybe noise cancellation in the camera does it job, I don't know - but in real life noise is much louder. Prusa i3 is my second 3D printer, first one is Monoprice Maker Select Plus, and it's way quieter than Prusa in normal mode - I should make a comparison video. So I am not convinced that those noise level are normal.
I contacted support regarding printing fan noise - I am convinced that it's just defective, and I addressed it the support.
As for Y-axis motor, I tried to insert thin (1 mm) piece of rubber foam between the motor and the frame, but it's too tight there, and I am afraid to break the motor mount when I tighten the screws, and also motor axis becomes not perpendicular to the belt. I also asked support about it.
I will try to re-print motor support just in case, and share result here.

Posted : 06/02/2019 4:47 pm
Patrick McNamara
(@patrick-mcnamara)
Estimable Member
Re: freshly assembled MK3 is super loud

The loud cooling fan is, unfortunately, "normal". You are hearing the PWM frequency used to control the fan speed. Anything other than 0 or full speed will have noise it in. How loud varies from fan to fan and printer to printer, but everyone has it. Also note that some people are more sensitive to certain sounds a frequencies.

Compare yours to this:

Now, that's a particularly bad example, but that is what my printer started out sounding like. There were several things going on: the Y axis bearings were too tight, the LCD housing was not tight enough, and the extruder gear tension was a bit high.

With a less squeaky filament, you can hear the bearing noise:

After loosing and tightening where appropriate, the fans are by far the loudest:

The last video is in silent mode, with the cooling fan at 100% and using a Meanwell power supply with a built it cooling fan.

Just some videos for comparison for you.

Posted : 06/02/2019 7:45 pm
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(@)
Illustrious Member
Re: freshly assembled MK3 is super loud

Well - I think you answered your own question about loudness: Making sound takes energy.

The Monoprice:
Print Speed 10 - 70 mm/sec
Travel Speed 10 - 70 mm/sec

The Mk3:
More than 200 mm/s

That's 3 times faster. A lot more wattage required for that 3x speed; more powerful motors, power supply. drivers, etc.

I don't see a noise spec for the Monoprice; but I just measured my Mk3 at less than 1 meter: 52-58 dB in stealth; 58-65dB in normal. My refrigerator makes that much noise.

Posted : 06/02/2019 8:17 pm
Holger
(@holger-2)
Honorable Member
Re: freshly assembled MK3 is super loud

Hello @ all,
thanks for this thread!
I could make a similar video of my MK3. Depending on the speed, the y motor generates considerable vibrations, which continue as part of the printer and shake the entire printer. I have created a G-Code file that allows the engine to be tested at different speeds.
My MK3 roars at F = 2850mm / min (43mm / sec) very loud.
Is that normal? What about your printer? What does the PR support mean?

greetings, Holger

M117 Y-Axis vibration Test
G28 W
M117 Y-Axis Test F1000
G1 Y0 F1000
G1 Y200
G4 ; Wait to end all movements
M117 Y-Axis Test F1500
G1 Y0 F1500
G1 Y200
G4 ; Wait to end all movements
M117 Y-Axis Test F2000
G1 Y0 F2000
G1 Y200
G1 Y0
G1 Y200
G4 ; Wait to end all movements
M117 Y-Axis Test F2500
G1 Y0 F2500
G1 Y200
G1 Y0
G1 Y200
G4 ; Wait to end all movements
M117 Y-Axis Test F2850
G1 Y0 F2850
G1 Y200
G1 Y0
G1 Y200
G1 Y0
G1 Y200
G4 ; Wait to end all movements
M117 Y-Axis Test F3200
G1 Y0 F3200
G1 Y200
G1 Y0
G1 Y200
G1 Y0
G1 Y200
G4 ; Wait to end all movements
M117 Y-Axis Test F4000
G1 Y0 F4000
G1 Y200
G1 Y0
G1 Y200
G1 Y0
G1 Y200
G4 ; Wait to end all movements
M117 Y-Axis Test F4500
G1 Y0 F4500
G1 Y200
G1 Y0
G1 Y200
G1 Y0
G1 Y200
G4 ; Wait to end all movements
M117 Y-Axis Test F5000
G1 Y0 F5000
G1 Y200
G1 Y0
G1 Y200
G1 Y0
G1 Y200
G4 ; Wait to end all movements
M117 Y-Axis Test F5500
G1 Y0 F5500
G1 Y200
G1 Y0
G1 Y200
G1 Y0
G1 Y200
G4 ; Wait to end all movements
M117 Y-Axis Test F6000
G1 Y0 F6000
G1 Y200
G1 Y0
G1 Y200
G1 Y0
G1 Y200
G4 ; Wait to end all movements
M84 S0; stop the idle hold on all axis and extruder

2x Personal MK3IR-BMG09 (Full) BEAR + MMU3 mod., ...

Posted : 10/02/2019 5:30 pm
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(@)
Illustrious Member
Re: freshly assembled MK3 is super loud

I don't have to run a script to tell you some drive speeds of a stepper motor will become resonant and be louder than other speeds. I can further add my Mk3 is much louder than your old printer based on nothing more than specs.

If you are unhappy with the purchase, for whatever reason, why not return the printer and ask for a refund?

Posted : 11/02/2019 10:33 pm
FireHawk
(@firehawk)
Active Member
Topic starter answered:
Re: freshly assembled MK3 is super loud

Sorry for long break, and thanks for your comments.

I could make a similar video of my MK3. Depending on the speed, the y motor generates considerable vibrations, which continue as part of the printer and shake the entire printer. I have created a G-Code file that allows the engine to be tested at different speeds.
My MK3 roars at F = 2850mm / min (43mm / sec) very loud.
Is that normal? What about your printer? What does the PR support mean?

Thanks for the gcode, Holger! Did you test your printer with Y-carriage attached, or without?

I can further add my Mk3 is much louder than your old printer based on nothing more than specs.
If you are unhappy with the purchase, for whatever reason, why not return the printer and ask for a refund?

I did not get it, sorry. Noise levels are not specified for both printers in specs.
I am more than unhappy, that's true, but local seller where I bought this printer don't want to hear about return - he damn sure that I am just an idiot who cannot assemble a 3D printer.
Important thing here: I assembled 2 more printers bought directly from Prusa shop, and they don't have a problem with extra noisy Y motor (but PSU are resonating on both) - so mine is definitely defective.
TL;DR
I managed to make printer quieter just by printing with feed rate approx. 30mm/s, and then adjusting speed manually to desirable noise levels. I also reprinted Y-mount and installed noise insulation between mount, frame and bolts. I don't like decreased rigidity on Y axis after this (causes ghosting), but it's better than this crazy noise.
Now the worst thing is print fan noise - it's louder than my voice, but it's only the case when fan speed lower than 100% (and higher than 0). On 100% it's much quieter.

Posted : 15/03/2019 10:29 pm
vintagepc
(@vintagepc)
Member
Re: freshly assembled MK3 is super loud


Now the worst thing is print fan noise - it's louder than my voice, but it's only the case when fan speed lower than 100% (and higher than 0). On 100% it's much quieter.

Update to 3.5.2 or 3.6.0; the PWM frequency has changed and the whine is gone (as is most of the PSU/heatbed clicking)

Posted : 15/03/2019 11:25 pm
FireHawk
(@firehawk)
Active Member
Topic starter answered:
Re: freshly assembled MK3 is super loud



Now the worst thing is print fan noise - it's louder than my voice, but it's only the case when fan speed lower than 100% (and higher than 0). On 100% it's much quieter.

Update to 3.5.2 or 3.6.0; the PWM frequency has changed and the whine is gone (as is most of the PSU/heatbed clicking)

Oh, thanks - will try tomorrow! I was on 3.5.1. I also ordered MK3S upgrade kit - I have a feeling that it can resolve few problems with noise.

Posted : 15/03/2019 11:30 pm
Holger
(@holger-2)
Honorable Member
Re: freshly assembled MK3 is super loud



Thanks for the gcode, Holger! Did you test your printer with Y-carriage attached, or without?

A few weeks ago I did a few tests with the y-stepper motor, and even changed the original stepper in vain for the new 1.8 ° LDO cool type. The experiments were carried out in stealth mode. For testing, I wrote the G-code for different speeds. This allowed me to find out the resonant frequency of the frame. Tested in complete condition, as well as with and without drive belt. I loosened the stepper and tightened it again. During certain speeds of the stepper motor, the frame begins to oscillate at its resonant frequency. The vibrations are transmitted to all components of the printer. The linear bearings, the PSU, Einsy housing and the LCD get into vibration and produce more or less loud noises.
Misumi linear bearings (120 ° C stainless steel types, HT greased) and guide rods are installed in the printer. The Misumi bearings are no quieter than the original components. I exchanged the u-bolts for plastic bearing blocks and did much more changes. As a result, there was no improvement in the vibrations and the noises, only the resonance frequency has changed a little.
Next, the original frame is swapped out for a more stable frame (full Bear). I will then find out if anything changes in the vibrations.
Ultimately, only a few components of Prusa will remain in the printer. 😉

Greetings, Holger 🙂

2x Personal MK3IR-BMG09 (Full) BEAR + MMU3 mod., ...

Posted : 16/03/2019 6:04 am
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