Y-Axis Causing Bed Shake; Ruining Prints, Making Kittens Cry.

Hey, all. I'm having a pretty big problem with my RoBo. I removed the birch to re-solder a broken thermistor and install some bed-leveling upgrades (and study everything to get a better understanding of this newfangled contraption), and since then the print bed has started shaking a lot every time there is movement along the Y-axis.

To test its severity compared to movement along other axes, I loaded up a seismometer app and taped my phone to the print bed both during a print and while controlling the printer manually. While the X and Z axes caused negligible amounts of shake, the Y-axis caused very prominent spikes on the graph, the effect increasing as the bed traveled farther from the center. Furthermore, it takes a couple of seconds for the bed to settle after it starts shaking.

The effects of shake have ruined every single print I've attempted since it began. Because there is so much variation in spacing between the bed and the extruder during shake, perimeter layers are not sticking together and infill becomes a stringy mess, causing what prints do survive past the first couple of layers to be very brittle. Any feature smaller than a few millimeters will not stick to anything at all.

I've tried removing (separately) the modifications I've made to the print bed (thick springs around the screws that attach the birch to the drawer slide, Cambo3D's printed bed corners, 1/8" borosilicate glass, and the thermistor) to see if they are inadvertently inducing shake, but nothing had any effect. At this point, I am thinking that tension from those springs I installed may have bent the drawer slide.

Does anyone have suggestions on what can be done to fix my printer?

 

Side-question: does anyone know where I can get replacements for the nuts connecting the birch to the slide? I lost one of them and nothing at Home Depot can fit in that tiny slot.

 

Something has happened to the rails more then likley, If you move the rails back and forth does it feel smooth? Do they look bent?

 

They don't look particularly bent, but I do kind of want to say that movement isn't as smooth as it used to be (though that could be psychological since I didn't check until I was troubleshooting). Also, the upper rail is kind of "floating" on the lower rail. Not sure if it's supposed to be doing that, but gravity may have some objections. I haven't mustered the courage to take the slide apart to check (I'm really bad at reassembly).

 

The springs I'm using are really thick, and it takes a lot to get them to compress, let alone bend laterally. But I removed them and put the standoffs back on while troubleshooting and there was still a lot of shake.

 

I'm using the original birch and heater with a plate of boro glass sitting on top.

 

It's giving more resistance than it used to, but I can't feel any bumps. I wish I could give more technical answers, but a lot of this if outside of my sphere.

 

Sure. What part of the printer should I be recording?