vc3.1 new toolhead
been running the EVA perfectly fine for a while now, just switch to the RRTH (or at least my modified version of it) and I can not fix a resonance graph in the same way or with the same ease as I used to.
first run didn't seem too bad, decided that the lower belt needed to be tensioned more but I had run out of movement on my tensioner so I had to pop off the grabber and trim down a few teeth and now it is even worse.
I'm gonna walk away from the machine for the rest of the day so any input (heh) I can act on when I get back would be super helpful.
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hmmm no timstamps on graphs, so that's kinda useless
here was my first one:
second
third
I did try to match Hz when plucking the belts inbetween 2 and 3, but obviously that didn't seem to help
Not sure if applicable, but I had a similar situation when the belt was slipping in the belt tensioner, eventually popping out.
which? the front or back grabber?
thats... better
The lower back one (the one with the tensioner screw) on the regular EVA 3.1 toolhead. I changed belts from the stock Rat Rig to Gates high temp and the new belt slipped. Ended printing new tensioners and now it seems OK so far.
But...
That's the good belt?
:thonk2:
ayy yo
I can work with that
could this mean my upper and lower are actually switched?
yes
wait
no
it is correct, still doesn't make any sense though
this is holding the umbilical
Deja vu, had something similar, tightened the lower in tiny baby steps (and may have loosened the upper tiny bit) eventually the second peak rose, first peak lowered and the 3rd flattened mostly.
:thonk6:
I wonder why
Your second peak is starting to rise and first is going lower, I would keep going.
gotta wait for the new grabber
I can't tighten my right belt any more than this
my tensioners have the same amount of travel as the vc4's
These still looked fixable.
The last few I am at a loss, no ideas.
how do you mean?
You went from 2 peaks to one, puzzling to me because that is not how mine went.
going from this to this seemed like the biggest improvement to me, and I just needed to tension the bottom belt more.
the problem is I ran out of travel for tightening the bottom belt, so I started to loosen the upper belt.
I think the third or second to last are my best recordings
I had loosened the upper belt enough to an acceptable range
but in those last 2 now I'm loosening it too much, and I'm back to being limited by the travel of the bottom belt
my next steps are probably to trim off another couple of teeth from the bottom belt
That is probably the best course of action since you are out of travel, too bad, the upper reading of the last two looked salvageable.
after this one I ran out of travel on the lower again. so I loosened the upper and got the last one. guess I still have to trim a bit more.
:pepe_hands:
I think mikl mentioned it recently, but apparently the taller peak is the looser one? That helped me with my graphs
I have... Definitely been doing that backwards then.
ay yo
You and me both apparently. Going better now?
all I did was run it again while holding the umbilical
tightened upper just a bit
again tightened upper just a bit
but also
held the orbiter during the tests
I noticed it was vibing quite a lot during that 50-90hz span
loosened lower just a bit, still holding on to the umbilical and orbiter
loosened bottom, tightened upper, both just barely...
I'm really not sure if this is getting better or worse
definitely worse
tightened both slightly, trying to get back a few steps. upper more than lower.
also I'm not holding on the orbiter and umbilical anymore, so that's why 50-90 is messy again.
tightened upper just a bit
slightly tightened upper but somehow its peak went higher
tightened both, upper more than lower
I want to keep poking at this but I really don't know if I'm actually progressing in the right direction
Welp, went to start trying again and the upper belt ripped out of the grabber
There are lots of good videos out there in belt tensioning (and a few suspect ones). I kind of like this one as it has good practical advice even though some stuff seems wrong (I think we should have two peaks not one in our belt tension graphs, one for X resonances and a lower frequency one for Y resonances)
https://youtu.be/zfnWsBOt3_8?si=JNjIDw0KR5r9_sTj
Reth
YouTube
Part II: Belt Shaper - How to read your belt shaper graphs: it's a ...
This is part II of resonance testing segment.
This is a long explanation of Belt Shaper - Please let me know if I forgot anything, something was not clear or was confusing. Something I forgot.
Data taken from:
3D Printers & a whiteboard How to Read and Analyze Input Shaper Graphs Generated by Klipper
https://www.youtube.com/watch?v=M-yc_XM8sP4...
I'm gonna have to get new belts
they are like... exactly as long as they need to be, which means when I went to adjust the gripper I can't tension it and add on the gripper at the same time.
I did redesign my tensioners as well to allow for more travel, but that's a story for another day
finally got a new belt
tightened lower belt just a bit
loosened top a lil
:pepe_cheer:
https://discord.com/channels/582187371529764864/1198381287208132618
^ for reference. the exact same build but EVA.
I... have no idea what is going on with that X
also, I find it real funny that vc4 people had so much issue with docking a carriage on the gantry because mine has had two carriages docked (top and bottom rails) even before that linked thread.
so like... looking at what those graphs looked like I guess it could be that but looking at my old graphs I'm hard pressed to say that might not matter as much.
My bottom belt is definitely going up and down when it moves
I'm going crazy
Now try the graph heat-soaked and be prepared for a big surprise. Someone mentioned it the other day so I did a comparison between cold and heat-soaked, both shaper graph and belt tensions and it is like two different printers. Just trying to make you go even more crazy.🙂 The heat-soaked ones look a lot better than the cold.
That I am prepared for
what I can't figure out is why my belt is running up and down
It is normal. They cut the belts from a circular tube (?) so the teeth are slightly unparalel to belt length.
At least that's what I heard.
No, the belt is running a good 2-3mm up and down on the bearings, this is not good.
Also I saw the dialogue surrounding that in the other channel and it is... snake oil. LL belts have always been made the same way and it has never been an issue before. at the VERY MOST you'll have one continous fiber at the top and one fiber at the bottom that are on just slight of an engle that they come out of the top/bottom of the belt (this is why people erronously think their belt is 'frayed' a lot of the time) but the remaining threads inside are not at a significant enough angle to cause any noticeable walk.
if your belts are walking it has NOTHING to do with reinforcement thread angle and I'll fight anyone on that stance. I won't say it doesn't matter or doesn't have any effect, but this effect is so negligible no one should use it as a scapegoat to explain away their shitty attempt at a belt path
You are correct; it is definitely not normal for your belts to be walking up and down the bearing stacks. For this to be happening, you have perhaps one or more of the following issues.
1. Damaged belts
2. One or more of your bearing stacks is not perfectly vertical.
3. You have a bent (unlikely) stepper motor shaft.
4. One or more of your stepper motor bearings is stuffed.
5. One or more of your bearing stacks is sitting at the wrong height, and your belt is rubbing or riding on one of the bearing flanges.
6. The belt retainers on your print head are at the wrong heights.
7. Your belts are sitting crooked in the belt retainers in the print head (have personally encountered this).
SOOO... I took apart everything and have been waiting on new bearings because one was definitely clicking and dead.
I don't think a clicking bearing would explain the walk, but I figured in the process I would probably resolve your resolutions 1 through 6.
... But yeah, ever since then I have been wondering if it was just grabbed on an angle and that I should've checked that, so now that you said it here too I'm pretty sure that was it.
Guess I had to do the rebuild anyway, but I could have lived with clocking for a little while lol