When my machine fails to run, i stop and reset manually jog z axis down any amount, and return to automatic and start the program again and it will run thru properly from start to finish..
That led me to believe that it was maybe an issue with not having simultaneous rapids, because if simultaneous rapids is turned off the controller has special handling instructions for the z axis.. something like performing z motion first heading away from part, but z motion last heading towards the part..
And i have phoned autocon/dynapath in numerous occassions, and noone has ever returned my calls or emails.
when i called the manufacturer and spoke to an actual person he said my machine was before his time and he would have to ask someone else what to do and call me back..that was 2 months ago..