Z-axis noisy  

RE: Z-axis noisy

carl... Perhaps this is a different issue, but here's a problem I had with z Axis noise and how I solved it: https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/z-axis-noise-problem-solved/ .  The z Axis steppers do not seem to run as smoothly as the x and y steppers on my machine. Maybe it just the fact that there are two of them stepping simultaneously. Hope this helps...

RE: Z-axis noisy

So you put dampers between the motors, the Z-axis top and the aluminum frame?

RE: Z-axis noisy

I found the problem. Unfortunately the a problem in the EINSY miniRAMBo board.

So, what is causing the problem. There are two Z stepper motors on the same TMC2130-LA driver. The result is uneven stepping between the left and right Z-stepper motor. Because of the back EMF (electro magnetic force) the stepping will never be smooth. Using a TMC2130-LA is probably a bad idea. 

RE: Z-axis noisy

Posted by: carl

I found the problem. Unfortunately the a problem in the EINSY miniRAMBo board.

So, what is causing the problem. There are two Z stepper motors on the same TMC2130-LA driver. The result is uneven stepping between the left and right Z-stepper motor. Because of the back EMF (electro magnetic force) the stepping will never be smooth. Using a TMC2130-LA is probably a bad idea. 

Except that a lot of us are using that board and NOT having noise issues.   I suspect there is something wrong in your build.  For example, the Delrin T-nuts are self lubricating, no oil needed.  Bearings specify grade 2 grease.  And a common problem with the Z-Axis is the dust covers are too close to the motors and cause binding on one side.  Too much X-Axis belt tension can also cause Z-Axis issues.  Another less likely possibility is a broken wire on one of the motors.  

RE: Z-axis noisy

So you put dampers between the motors, the Z-axis top and the aluminum frame?

carl... No, the rattles were actually inside the LCD module due to loose parts. That's where I put the felt. The rattles were excited by the z Axis vibrations and added quite a bit of noise. You may have pinpointed why the z Axis motors seem to vibrate more than any other motor, however. I use steppers in my Arduino projects quite a bit, and they can be a mystery to get running smoothly. I suppose it was easier running two motors rather than just one with a belt on top. Maybe there was too much play in that solution, or side-to-side adjustment difficulties. Could be an easy mechanical mod, but I ain't gonna do it!

RE: Z-axis noisy

A belt drive Z is problematic on several levels. #1, belt stretch causes a X-Axis misalignment that can't easily be tweaked out. Imagine having to manually "recalibrate" Z lead screws to do an X-Axis level every other print. Arggh.  I'd stop printing.  And, there really isn't anything wrong with parallel drive for stepper motors. Sure, if one is carrying a higher load than the other, problems can crop up. But in this application there isn't any reason for load imbalance except an assembly issue. 

RE: Z-axis noisy

I think I found the issue. I measured the coil resistance of all my steppers. 

The combination of one stepper driver and one of the steppers that is probably outside the specs 

RE: Z-axis noisy

Are you using 4 wire measurements? If not, that 0.3 ohm is meaningless.

If using relative measurements, if may describe a crimp issue... but I still doubt the numbers unless great care was taken to minimize errors.

RE: Z-axis noisy

Z-axis is very loud

carl...I found that one very powerful way to diminish z Axis noise is to modify a certain value in the PrusaSlicer program before slicing. Go to Printer Settings>>Machine Limits>>Maximum Feed Rate Z, and change the default value (12) to something like 6. Slice the model and print it, and you should have virtually no z Axis noise. (the z Axis motion will be slow, of course). The problem comes from the stepper motor exciting some natural structural frequencies in the printer. I used an acoustic spectrum analyzer to view what was happening, and there are many natural frequencies in the 1-2 kHz region that get excited by vibrations of the steppers if the speed is set to 12. Lowering that speed lowers the excitation frequency, and probably its magnitude, so the natural modes are not excited. I played with this variable, and found that a value of 10 is still quiet, with just little loss of speed. Give it a try...

RE: Z-axis noisy

Ich habe das gleiche Problem. Das kann wahrscheinlich nur von Slier kommen, wusste aber nicht wo man das einstellen muss.

werde es demnächst ausprobieren. Vielen Dank.

RE: Z-axis noisy

This was so helpful. Thanks Jack. You are so right

RE: Z-axis noisy

OG...As I was building the extruder assembly I wondered why the design was such that the stepper motor was cantilevered so far away from the X-axis rails. The motor is heavy, and Z-axis stepping excites a vibrational mode where the motor bobs up and down in response. A better design would have been to put the motor behind the rails, with the extruder/heater block left in front of the rails. That layout would have moved the combined center of mass of the entire extruder assemble much closer to the rails, and I believe that would have helped with this issue. I thought about designing and printing out that layout, but most likely it would have required an extruder gear with a longer shaft, so it's beyond what I could do.

RE: Z-axis noisy

I have just finisched to assemble the printer, and I have the noise problem too and it is unbearable. I have several cheaper printers that are a lot more silent than this. I hope Prusa will be able to find a solution 

RE: Z-axis noisy--Just Ran an Experiment

I hope Prusa will be able to find a solution

 I just did two identical test prints, one in Normal Mode with its default settings, and one in Stealth Mode with its defaults, except for Maximum feedrate Z, which I lowered from 12 mm/s to 6 mm/s. Some observations...

(1) Prusa Slicer predicted 32 minutes for Normal Mode, and 33 minutes for Stealth. So there's not much of a penalty for the change.

(2) The biggest difference in noise was for X and Y motions, which are done at 200 mm/s for Normal, and 100 mm/s for Stealth. There's very little Z motion during the actual print, and frankly I didn't detect any difference that I could attribute to my change in Z rate.

(3) There are some larger Z movements before and after printing, and they may have been louder for Normal, but that's only a few seconds.

(4) Prusa firmware is in charge of rates for the bed leveling actions, and, yes, Z axis moves did buzz significantly.

So hang in there. I've been printing with my Mark/3S for three years now, and it has been bulletproof, with excellent prints nearly every time. Total cost aside from filament has been two new nozzles. I always print in Stealth Mode, and really can't hear it if I'm more than 5 M away, or the door is closed in my office.