Laser is grinding going ballistic and not framing correctly

This is interesting. We’re all hoping to help you diagnose and solve the problem.
LB has a variety of motion options that can send the laser head in many unexpected directions, but the reality is it usually goes exactly where we’re telling LB to send it, unless of course you’ve discovered a LB bug, a firmware bug, or you have mechanical failure. The first assumption should always be that we’re mistaken and telling LB to go somewhere it shouldn’t, in general or for a specific design or job.

Case in point, I can draw a small 100mmx100mm square in the bottom left corner of the workspace and if I use Start From: Absolute Coords it can frame or cut just fine,
but if I Start From: User Origin with user origin at X0Y0, and my Job Origin is bottom right corner of the shape, and I have Cut Selected Graphic on, Use Selection Origin on, then frame or attempt to cut the laser head will crash in or near the bottom right corner.
Same shape and design, different setup. I’m just trying to say its easy to make these mistakes at times.

The gcode in the console is from a Frame operation, the first stream is starting from Absolution Coords, the second is User Origin as described above. The first was fine, the second crashes on the “G0 X-149.993Y-49.993” move from X50Y50.

Give this test case a try in Absolute Coord mode, moving the square around on your workspace and framing it. I don’t recommend that you try the User Origin case that forces a crash, no need to force a crash. But eventually use different mix of Start modes and selection modifiers and you’ll see how those affect outcomes.

Either this will demonstrate you may have had a job setup wrong or you will find a mechanical issue in certain areas of your workspace, or some other discovery that may lead to a solution for you.

Another item to consider is that at certain speeds a stepper motor can make a growling sound, usually very low speeds. You mentioned grinding, do you see evidence of metal or rubber shavings ?

Good luck.