Situation: Z height decreases as a program is run. Possible causes? Z steps/mm is too large? Too small? Z axis is binding in + direction?
Usually the rapid speeds where set incorrectly or not at all and the processor is just not moving the axis because the number of steps is too high.
Without a lot more info we can’t help. Board, Steps, drivers, speed, rapids, cam program?
Can you explain that a bit more?
Is it lowering as time increases? Raising?
Is it lowering as it moves in one particular direction? (((Like, is it lower on the right than left)))
Does it lower only when doing cutting? Can you move it down by some amount and then back up?
Maybe a picture of the job you’re doing will give us more clues.