Bad resonances after a few upgrades
I installed FMMM. dampers, and 48V, and my resonances after are worse or equivalent to before. I heard a bit of noise coming from the casing of the toolhead endstop, so I disassembled as much as I could. I can still hear some noise on Y, but the only thing left is the ball-bearings in the carriages.
I replaced the cable to the ADXL with an ethernet cable. I removed all panels, insulation, clips, webcam. I have rechecked all fasteners on the gantry. I have straightened the gantry and evened out the belt tension. The printer is on a floor on a semirigid rubber mat. Removing some parts has reduced input shaper recommendations in some cases.
I'd really appreciate any suggestions on this one.
25 Replies
how does the other axis look?
Here's another run.
interesting, those other peaks are perfect 2nd and 3rd harmonics, the base frequency being 55hz, 2nd harmonic 110hz, exactly twice the base frequency and third harmonic at 165hz at 3 times base frequency!
so that isnt really "noise", its undampened harmonics from the super light, bare toolhead
i suspect those will be dampened out by normally having the heavier components like the extruder and hotend, and are thus normally not too visible
Okay, I'll load everything back up. It was not great before I unloaded it. Here's a video too.
At about 20 seconds, you can hear the 50ish hz range with, what sounds to me like a ball bearing type sound that comes right from the toolhead. The other spikes sound like they come from elsewhere.
the higher range kinda sounds like the belts rattling against the frame? could it be that?
the 50hz range does sound a bit strange, very metallic as well
It could be the belts against the frame, that does sound like where it is coming from.
They're pretty tight, but they're not touching while stationary.
Rather, the higher fq sounds like it comes from the belts, the 50hz sounds like the printhead.
the belts might still need some more tension, you can really see the upper belt going in the video:
I'll run another tension check, but this was yesterday.
I know that only does relative tension
since i also had quite shakey belts, turned out I was way too loose
Okay, I'll give that a read and report back. Thanks for your help with this.
np! I run practically the same setup as you and have encountered this exact issue
or at least, roughly the same
its a Vcore 400 right?
300
ah okay, well most things should still apply with given upgrade setup, just higher frequencies
Belts about 94hz from what i can tell with spectroid
There's a peak around 50hz, but it's also at a spike in the noise floor
Here's a picture with HVAC turned off
@docdoyle Could you tell me if I'm interpreting this correctly?
a bit hard to see, the lowest peak always lines up with the base frequency, which I would say is 50hz
so in that case it would need to be tensioned into 86-100hz range as per the document
the fact that the sound is so short also suggests that its loose, since it tends to sustain a bit longer
Okay, I'll try tensioning it up and see if the base frequency goes up with it. Thank you.