Hello, I am trying to mitigate 2 resonant frequencies and I have tried many different things to do so but the highend frequency will simply not go away. I keep getting rippling in my calibration tower that does not go away. At the bottom of the resonance documentation, there is mention of another graph_shaper.py that could help in mitigating 2 frequencies that are not close to each other. I replaced that file in the scripts folder but I did not receive any different answer when processing the data. Here is the result:
You can clearly see a high frequency rippling that does not go away and then a low frequency vibration that eventually damps itself completely. Any help in this matter would be appreciated. Thank you.
Thank you for the suggestion. I have ordered linear guide rails for my delta to see if this helps. However I will say that the current carriages do not seem to be binding. I run them up and down with my hands and there are no hard spots.
What I am most concerned about is the rippling that is located on the X side. As you can see, the rippling never solves itself and reduces to zero. It maintains itself all the way to the edge where strangely you start to see another frequency vibration which shouldn’t be there because the print head is on a straightaway heading for an edge. Very confusing to me. I am starting to wonder if the stepper motor is dying in the “C” location and that is why it is bouncing back and forth between a step causing the rippling.
I have tried turning ON and OFF interpolation, stealthchop; increasing and decreasing the amps on the motors; increasing and decreasing the speed of the print… and nothing has affected it much.
I thought that switching to 48V would help the steppers mitigate vibrations faster, but it had no effect at all.
The most that I was able to obtain is that half way between the X and the corner, the ripple would stop but it would be pretty random from the bottom up where the accelerations are changing every 5mm height.
I am really out of ideas but I might consider getting new steppers.
It did cross my mind that perhaps the motors are already too strong and as a result the whole system does not provide enough damping to work correctly. It is weird though that this hasn’t always been the case. I did not see this issue more until recently when I mounted the extruder on the effector to obtain direct drive and be able to use klipper again. This added weight and in turn inertia and so I would only expect lower frequency vibrations to increase, not higher frequency oscillations.
For a sanity check, I will probably install my smaller NEMA17s and see how that will affect things.
You might do this, but it will not help. Like Sineos said, it is most likely a mechanical issue: If you see your measuring result above (resonance_x), as expected, the “first” (and should be the only one) resonance is almost 100% X-Driven while the second at 110Hz has a visible Y-part (green line) and a smaller Z-part. So something is accelerating your probe to Y-direction (and a little to Z, too) although it was only attracted to X. This could be a loose screw (broken part, loose bearing, …), that allows to turn a mass out of the Y/Z-Plane (X-direction). Noone can compensate a loose screw and this is just not the intention of compensation…
Sorry for the bad news!
Thank you for your response. I will definitely investigate this more thoroughly and see if there is anything loose that is causing the problem. Perhaps the bracket that connects the extruder to the effector needs to be more robust to prevent its own counter ringing.
It looks like just like the thread Sineos pointed out, and Berggipfel stated, that the printer has become so stiff that it is producing more high frequency resonance.
I have removed the direct extruder from the effector and it did nothing, or if it did something, then it was very minute.
I did replace my motors just in case for a sanity check, thinking that perhaps their lesser power would prevent the high frequency resonance. That didn’t change anything.
Then finally I realized that the only difference in all the axes might be the belt tension. So I started playing around with those and it seems that they made the greatest difference, however they did not yet fix the problem completely.
I am starting to think that I need to put some sort of dampers on the delta arms to capture the higher frequencies. But then I am adding more weight to the effector…
Few months ago I did build an enclosure around the printer and I suppose that must’ve stiffened the whole structure. However I do not remember this being an issue from the get go.
I know this may do nothing, but I do remember that the TMC5160 caused a lot of ringing on one of my printers and going back to 2209s fixed the problem. I may have to at least try it.
Just continue your quest
(I still put all my bets on a mechanical issue like binding axes. The high portion of very low frequencies between 0 and 30 Hz are very unlikely otherwise AND fully contradict a stiff printer)
Keep in mind that I am dealing with a delta printer with long delta arms that move probably 300-400g of weight at 340mm distance. So when the vibration of those things can not be absorbed into the frame, then it will remain ringing in the effector.
My next project will be to replace the delta arms with carbon fiber arms and see how that helps. I see the current arms slightly vibrating and maybe this will help isolate the resonance some more.
When I replaced the motors, I checked all the delta arm carriages and there was no binding and that is why I am very confused with this situation and your suggestion. Everything moved very smoothly through its range of motion.
Is there a way to be able to turn on a certain frequency from the resonance tester and keep it there while I adjust the belt tensions? It would allow me to tune the belt tension perfectly. I would just set it to the resonance frequency and see how it changes as I adjust. If there isn’t a way, this should be a feature upgrade I think. Ideally I would like to be able to set the resonance frequency and then start touching the various connected components and see what is resonating the most.
Keep in mind that I am dealing with a delta printer with long delta arms that move probably 300-400g of weight at 340mm distance. So when the vibration of those things can not be absorbed into the frame, then it will remain ringing in the effector.
My next project will be to replace the delta arms with carbon fiber arms and see how that helps. I see the current arms slightly vibrating and maybe this will help isolate the resonance some more.
When I replaced the motors, I checked all the delta arm carriages and there was no binding and that is why I am very confused with this situation and your suggestion. Everything moved very smoothly through its range of motion.
Is there a way to be able to turn on a certain frequency from the resonance tester and keep it there while I adjust the belt tensions? It would allow me to tune the belt tension perfectly. I would just set it to the resonance frequency and see how it changes as I adjust. If there isn’t a way, this should be a feature upgrade I think. Ideally I would like to be able to set the resonance frequency and then start touching the various connected components and see what is resonating the most.
