Z changed by 1mm

Z went 1mm high yesterday after a lot of printing so I lowered it. Just did 2 hours of printing all fine. Then when I started the next round it apparently dropped down and just ruined my pei sheet dragging the nozzle through it and taking all the texture off. It's not a heat soak sag issue. This was literally from one minute to the next. I don't understand
2 Replies
blacksmithforlife
Did you save it to printer.cfg?
foreign-sapphire
foreign-sapphire7mo ago
Bah, just found it. Z probe mounting screws had come loose. Great