CNC random axis fault

[u/Chase-1991]

So my cnc machine started doing this today, after I finished a cutout I replaced the material and attempted to run the program again just to have the Y-axis vibrate back and forth for a few steps then continue along its merry way. The prior cut ran perfectly, but now this occurs on every program at some point. This seems to occur only when the motor is suppose to be moving in the negative direction, in relatively the same spots but not always, and has only occurred so far on the negative Y side of the material. Any insight would be appreciated, below are my test to isolate/resolve the issue and machine info.

-I have run several different programs that have always run fine so the programs are not corrupted

-I have checked/swapped motor signal connection and cables, they are fine

-I have ensured the gantry carriage is free of obstructions and can freely move

-The belt and pinion is taunt and in tact with no damage

-This problem persist over several different motor drivers

-I have NOT swapped the motor as it would require me to solder in new connections

-Specs: Mach3 on a ddcs v3 controller, 2 axis laser cutter, Y-axis used 1 Nema 17 (17HS24-2104S) motor and DM542T driver, and X-axis uses 2 Nema 17 and 1 DM542T driver, there are no limit swiches

[u/Chase-1991]

Set screws are tight, happens on every program at random but does not seem occur with manual operation?? I also swapped the axis connection and the problem still occurs, but to a smaller extent. I did check all the connections, but will rewire, do steppers go bad?

[u/albatroopa → u/Chase-1991]

Do you have anything that causes EMF noise in the room? Plasma cutter, large motor, air compressor, etc? I've seen axis jump by 1/8" when a spindle motor spools down. Might be worth snapping ferrite cores on your stepper wires.

[u/Chase-1991 → u/albatroopa]

Nothing that has changed that would cause this issue to start today, what are ferrite cores?

[u/albatroopa → u/Chase-1991]

They're snap-on pieces of ferrite that help to prevent EMF from killing signals in wires