Answered Table calibration / alignment

There are three reasons it will grind

1) it is trying to move further on the axis than it mechanically can.
2) The belt is loose and the stepper is skipping
3) something is blocking it from traveling the full distance

The grinding is the stepper trying to step and failing.

Check the HOME switch on that axis (the bed is the "Y" axis)
When it homes is that switch closed? (home it and lift the bed plate to see if the switch is made). It can get a false home if the switch or wires are bad where it sees the switch as closed when it really is not. In that case it homes to the wrong Y position. There is no max travel endstop so if it does not go all the way home it will then overshoot when it tries to go to the far end of the Y (it knows where HOME is and then just does math to see how far it can go).

If the belt gets too loose it will slip and the stepper will loose track of exactly where it is and that can cause this.

Lastly make sure no wires or anything are getting in the way of the bed travellling. Lift the plate and watch the wires as you manually move the bed/rails from end to end. If the wire loom is getting in the way it will stop the bed from travelling and that will cause this as well.

 

The little bracket that holds the ribbon cable can fall down and cause issues homing, make sure it’s not hitting.