Suddenly , Every time I hit the Kill switch on the Tormach PCNC440,
the head continues to descend in the Z axis, until it touches the stock (G54 Z).
No matter how many times I hit the kill switch.
The only thing different is I have used the Tormach Passive probe to set the G54.
Can you clarify what kill switch you are referring to?
I have a 440 and the physical (red) eStop should halt all movement instantly. If that is what you are pushing and it isn’t stopping motion, your machine needs to be put out of service until you figure out why it isn’t stopping all motion…
If you press the estop and the motor loses power, then the spindle head slowly drops down until it is resting on your stock then your z-axis break needs some attention.
I hope the adjustment continues to be a fix for you…I went through this a couple years ago with my 1100 and Davie was right - it was the brake system on the Z-axis motor (wouldn’t lock when power was removed from the machine so the head would slowly descend after powering the unit down). A new motor was the permanent fix in my case, no issues since.