Slowly carving too deep

As the carve progresses it slowly gets deeper and deeper towards the end.

Looks like Z axis is losing steps. could be loose pullys or improper calibration or any number of things.

Search the forum for “Z axis losing steps” or just Losing Steps…

there is a TON of information on how to troubleshoot and correct this

OR your bed isn’t level.

Or the bit could be pulling.