VC4 300 frequency response
I know from the docs that this graph indicates binding somewhere but I can't for the life of me figure out where. The only thing I can think of is that my belts are overall too tight? Any suggestions on things to check and walk through. The gantry appears to have free range of movement on both X and Y without any noticeable issue (other than normal disengaged/powered off stepper drag), the belts don't move up or down on any of the idlers or pulleys. I'm just at a loss and being too tight is about the only thing I can think of.
Solution:Jump to solution
nice you got what ever that was binding unbinded.. Your upper belt is tigher. Do you think you could loosen it by one tooth and get it back to the same tension? Otherwise its clean enough to run with if you want
13 Replies
I assume this is either a coreXY machine or a hybrid without the hybrid belts installed? First up your upper belt is slightly tighter than your lower belt as the frequency is higher but its amplitude is lower as it’s not the same length most likely between the belt clamps. Are you sure both belts are the exact same length? You have a little bump at the~35hz where you should have a bigger one. So something is dampening that as well. I would start by checking the belt lengths as you need them down to the exact same tooth count between the clamps. Start there and see if you first spike comes up as you get that fixed.
Correct, this is a hybrid machine still in native corexy mode (want to dial this in before adding the hybrid belts). I'll try to verify the belt length. Is there a straightforward way to do that without taking the belts out?
Updated graph after checking bolt torque and tightening things up (cables, etc). Still have to check belt length though.
you might be pretty close. The lower belt frequency is now lower than the upper belt. Try tighting the lower belt like 1/16 to 1/32 of a turn. Not sure why your first spike is so dampened. How tight are the belts?
They are fairly tight - unfortunately I don't have a lot of slack -- I clipped the belts when the instructions said to clip them which didn't leave me much to work with. In fact, I just went to adjust one by a tooth and it popped free - whcih means I'm goign to have to re-run an entirely new belt as I don't think I can manually pull it through. 😦
take the front tension block off its screw. That should give you enough to get it back to where you had it
I left about 6 teeth on each side to make it easier to work on the belts, even if it adds a little noise
That is brilliant and I have no idea why I didn’t think of that.
Holy crap! Loosened up the lower belt by 2 teeth and that's where I am now.
Solution
nice you got what ever that was binding unbinded.. Your upper belt is tigher. Do you think you could loosen it by one tooth and get it back to the same tension? Otherwise its clean enough to run with if you want
I can probably do that, but I think I'm going to leave it at this point. You can only futz so much before you want to put your head through a wall. 😉
Appreciate all the help.
if I get any layer shifts I'll definitely loosen it by one though - I was running a test print before I loosened the lower and was getting a couple of layer shifts which I think were because of tension on the belt, not 100% sure so I'll have to run some prints and see what happens.
check you y resonances as well to make sure you dont see any noise before you move on to the hybrid belts
and use the MZV numbers to add into your printer.cfg
