i was happily running a gCode to make a part. I had my soft limits set and thought I had no worries. The gcode contains a drilling operation, followed by a profile operation. The drill operation went perfectly, then the profile operation kicked in and did one profile cut perfectly. Then it moved over to the next cut, and sank deep into my salvage board, past where the soft limit was set.
Confused, I raised the spindle up, and to my shock, the settings on the z axis had been lowered almost an inch! I knew this because the stop limit had been lowered an ich from the top, which lowered the bottom stop limit and allowed the bit to sink deeply into the wood without the stop limit kicking in.
What can the problem be? Everything has been running smoothly until this happened.
It has happened twice so far. So it is not just a one time accident.