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Unique Input Shaper issues


New member
I've had a LDO 350mm Voron 2.4 that I've had for several months now. I've had good luck with it so far. I decided to recently change out the x-axis rail to a Honeybadger x axis rail because the LDO rail I had had a little bit of play in it.

After doing that though, I'm seeing some odd results with my Input Shaper though.

My setup:
  • LDO Voron 2.4 - 350mm
  • CW2/Stealthburner
  • Tap
  • Ebb36
  • TI Backers
Here are my Input Shaper graphs:

Room temperature:
After a 30 minute heatsoak (45c enclosure, similar results after a longer heatsoak as well)
Anyone know what is going on here? I've never seen Input Shaper graphs look like mine when I've done a heatsoak.

Things I've looked at:
  • Verified all screws (gantry related and in the toolhead/Tap) are tight
  • A/B belts are both tensioned to 120hz, give or take 5hz. This was done very recently right after installing the Honeybadger x axis rail
Could I get some input to what could be going on here please?


i've taken a bit of time to think over this as it is as you say a bit strange.
both the X and Y are reporting a resonance at 140Hz on an X axis ( i believe this is the bit your questioning? )
does this mean you can hear an audible ring when it does the resonance test?
this is intriguing to say the least and you would be correct in thinking that a resonance on the X axis when moving the Y axis is not normal.

looking at it logically, in reality i would be surprised if you could perform a move / set of moves that would induce a 140Hz frequency so you could discount it. at least for this size of printer. unless your going for the speed boat challange.
it might be being created by uneven belt tension (as you mentioned that belt tension was within 5Hz or so) so one belt is more dominant at creating movement before the other belt catches up.
personally i would try and get the belt tension as close at you can to each other (within 1 Hz if you can) and at the recommended tension. (i'm sure you may be thinking the same thing or have done so already.)
if so, did it change anything?

performing a heat soak would make the printer expand so all the joints and fixings would become tighter so would change the resonance every time it thermally cycles.
so technically it would change for every print, but doing a resonance test puts the printer under enormous strain and doing it too much can cause issues with the printer.

on the plus side both tests for the Y axis report similar results, so this would be what you would set for acceleration. 3400 - 4000 max.
as for the X axis i personally would set it as per your first test result. so 47.2Hz at 6600 acceleration max.
these values should work in reducing the ringing you will see on the prints.
lower frequencies tend to have a higher impact on print quality.

hope this helps and keep us posted on any updates.
would be great if you can figure it out