On what seems to be all larger prints (print time greater than an hour), both Z-axis stepper motors stop incrementing. My specs are:
Upgrade Version2 Toolhead (Hex hotend)
It seemed to have occurred after installing the Version 2 toolhead along with the firmware upgrade. I suspected it was the firmware upgrade so I rolled back to the 2014 Q4 firmware (which I believe was still newer than the original firmware I had on the TAZ4 since I purchased it Sept 2014) and reinstalled the Budaschnozzle and old toolhead. The same problem occurred.
The same print worked just fine prior to the firmware and toolhead upgrade.
After it stops incrementing and I pause the print, I am able to manually change the Z-axis, so I do not believe it’s mechanical.
The Z-axis does not move at this level, so it extrudes and rubs against the top-most layer