First, check the machine mechanically — is all the hardware holding the linear motion components secure?
Verify this by installing a 1/4" probing pin in your spindle, then pushing and pulling on it — if the machine moves, note how/where and investigate and address.
Hi there, Did you tighten the Ball Screw Coupling Set Screws? There are 2 on each coupling, one for the motor and the shaft. You also need to make sure the screws are on the flat part of the shaft. (one for each axis)
Looks like slop in the X axis. Z is shifting when X changes direction. Had the same issue. For me it ended up being the two screws that attach the Z to the X ball nut.
Power up your 5 so the motors are locked. Check your X, Y, and Z for movement by simply grabbing them and giving a good push and pull.
Wow guys, that was a quick response! I just solved it thanks to all three of you.
Powered up, push and pull: there was still some movement of the gantry on left Y-axis. I tightened the screws on the Y-motor (see picture) onto the ball screw and that solved the problem. Thank you so much, what a great community.