I'm getting a lot of bad cuts where straight lines are wobbly and symmetrical

I’m getting a lot of bad cuts where straight lines are wobbly and symmetrical shapes look distorted. I’ve noticed my Y-Axis is occasionally getting stiff, could this be the cause? I’ve tried to take a video and wondering what I should do next to alleviate the problem? As you can see, I’ve taken off the side panel to take a look at the belt, but not sure what I should attempt. Please ignore the awkward air assist routing, this doesn’t cause an issue and will be re-routed better eventually. When the power is off, the axis move freely (shown at end of video). I’m using a smoothie with Laserweb and jogging by 100mm in the video. Thanks in advance, this is a great community and I’d be stuck without the valued advice given here.

Just noticed the Y-Axis belt on right (Controller compartment side), seems more slack than the one on the left. Where can I tighten this belt to see if that’s the cause?

there is a tensioner on the very back right of the gantry, identical to the one on the right end of the gantry for the x-axis, you should be able to tighten the 2 screws to tighten the belt tension.

Quite a lot of gunk on right hand rail. Cleaned it off as suggested to me in another post now I’ve finally realised where it collects up. Will see if this helps. I guess the video still serves as a reference to anybody with the same problem in the future…

This is still happening after cleaning, will try tightening the belt as guided, thanks Joe.

At what speed are you cutting at. Moving the entire Y gantry takes more reliable torque than just the x axis laser head. When I first recieved my k40, the gantry was out of square and both side belts were not tensioned equally. This lead the gantry to bind a bit. Adjusting made it smoother, however my y axis cannot go as fast as the x. I think it’s reliable to about 250mm/sec. The x can go faster, around 300mm/sec.

I normally don’t go that fast. I get better looking raster engravings if I keep it under 150mm/sec. I like a darker looking engraving.

Also, it seems that the accelleration is quite hight. And probably the air hose is pulling on the gantry too.

Highjacking this post to test hash tags searching.