CoreXY - X-Axis Vibration Issues
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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 -
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?
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its allowed to move in one direction to counteract slight alignment issues but it can not rotate.
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I think I understand, I am trying to look at your thingiverse link but the site is sooooo slow a the moment!
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@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!
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@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).
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@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.
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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. -
@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.I have tried increasing and decreasing belt tension to no avail. Could it possibly be motor setting related?
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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. -
@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?
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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.
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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 -
@mrehorstdmd yes it’s preloaded. It is secured to a cross-brace by a few cap head screws.
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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
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@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.
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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
Printers: A FT-5 with the 713 upgrade bits, a custom MarkForged style, a small Utilmaker style, a small CoreXY from kit and a E3D MS/TC setup. Various hotends. Using Duets (2 and 3) running 3.4.6
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@fcwilt my thoughts exactly hence the slight rebuild. At least I can do it by only removing the top plate!
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@syko_symatic just press f5 untill it loads ...
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@fcwilt Having a think about it, the E3D design uses the fabtotum style corexy which places the belts in front and behind the x carriage. It is technically possible to move them both behind the carriage, would that help?
