CoreXY - X-Axis Vibration Issues

Syko_Symatic

Hi all,

I have recenetly finished building my first CoreXY printer. I have built several printers in the past (Prusa Style, Ultimaker Style and an IDEX) but I am struggling with the vibration I am having on the X-Axis.

Both X and Y are on linear rails and I have measured them with a dial to be as parallel as possible. However, it still seems that the X-axis rail is binding (possibly) and that is the source of my vibration issues?

Does anyone have any advice on this? Could it be a belt tension issue?

I would appreciate any input!

Thanks,

Veti

initialy i had the x rail fixiated but it cause loud vibrations on some moves.
i removed the fixiation and now the x rail can move slightly back and forth and the vibrations are gone.
see https://www.thingiverse.com/thing:2839395
the rail is just prevented from sliding out completly by a screw

Syko_Symatic

It's definitely something I can look at. I will have to model some sort of clamp for the rail. How does it stay "square" if it is allowed to move?

Veti

its allowed to move in one direction to counteract slight alignment issues but it can not rotate.

Syko_Symatic

I think I understand, I am trying to look at your thingiverse link but the site is sooooo slow a the moment!

Syko_Symatic

@veti OK! So I have created a quick and dirty solution! I am going to print it in a few minutes and we will see if that solves the issue!

Syko_Symatic

@veti So unfortunately it didn't help. My solution wasn't perfect by any means but it didn't change at all. Hmm... any other ideas? I know without the belts in ran perfectly, so it's obviously being pulled by the belts (as I understand is pretty normal with corexy).

deckingman

@syko_symatic Difficult to advise without a bit more information. All we know is that it's a CoreXY. Can you post some pictures -especially showing the belt arrangements. A bit better description of the problem would also help.

Without having much to go on, I could make a shot in the dark and say that it might might be uneven belt tension that is imparting a twisting force which in turn is causing the guides to bind. The "classic" CoreXY belt patter usually shows the X carriage belts being quite a distance either side of the centre line of the X carriage. So if your belts are aligned like that, and the tension is uneven, then you might be getting a twisting force, which might be causing the guides to bind. I use stacked belts running along the centre line of the X carriage but you may not be able to do that easily.

Veti

also check that there is no twisting of the belts on direction change.
i.e make a gcode file with rapid 5mm movement back and forth at high speed and look at the belts during this.

Syko_Symatic

@deckingman Thanks, I will try and add some more info.
The belt arrangment is stacked and looks almost exactly like e3d's tool changer machine. I have included a short video from the other night. The noise isn't an issue in that video as it doesn't occur until it's moving a little faster.

Link

I have tried increasing and decreasing belt tension to no avail. Could it possibly be motor setting related?

Veti

create a gcode that can replicate the noise.
Then while its making the noise try to narrow down the location.
the frame looks like it could be resonating at certain frequencies.

Syko_Symatic

@veti It definitely sounds like it's coming from the x-axis carriage. I am going to give tuning the acceleration and max speed a go. Any suggestions of a good starting point?

mrehorstdmd

Is the X axis linear guide a "preload" type? How is the X axis rail mounted so that it can slide? If it is free to move, it may be free to rattle, depending on how it's mounted.

Veti

how stable is the x carriage? Push the nozzle in different directions and see if there is play.
Also check the fans. I had some fans that created a rattle caused by the blades moving inside the fan at higher speeds. and banging on the casing

Syko_Symatic

@mrehorstdmd yes it’s preloaded. It is secured to a cross-brace by a few cap head screws.

fcwilt

Hi,

It's hard to tell from the video but are the belts on either side of the X slide parallel to the slide?

Frederick

Syko_Symatic

@fcwilt as best as I can get them. I’m going to try re-aligning everything again. Annoying, but I am going to wait for some new gates pulleys from E3D to make sure everything is the best it can be.

Or maybe I will re-align it all first? I can’t decide. Either way I will keep trying.

fcwilt

@syko_symatic

Well I think it has to be something about your build.

I built a D-Bot CoreXY printer and it has no binding issues at all. BUT it uses wheels-on-extrusion tech, not slides.

My next CoreXY will try slides.

Frederick

Syko_Symatic

@fcwilt my thoughts exactly hence the slight rebuild. At least I can do it by only removing the top plate!

Gear

@syko_symatic just press f5 untill it loads ...