Z axis uneven movement help

Hello after 2 years my z axis plunged 1cm while leveling after i did a carbon pieace alot of carbon dust, after that I tighten every bolt swaped the motor on z and y motor and blow with compressed air and tried again now while the piece is leveling I can see the z axis plunging like say 0.1 mm in one place then in other place it lifts like 0.1 mm and this happens what I posted on the photo any ideas

anton petrov wrote:

Hello after 2 years my z axis plunged 1cm while leveling after i did a carbon pieace alot of carbon dust, after that I tighten every bolt swaped the motor on z and y motor and blow with compressed air and tried again now while the piece is leveling I can see the z axis plunging like say 0.1 mm in one place then in other place it lifts like 0.1 mm and this happens what I posted on the photo any ideas

please post the gcode you are using, I don’t understand the problem.

a video of the problem happening would be good.

David Lang