Ok, got it to work... fixed the lens with some teflon tape to stay in place.
Engraving wood works cool, have to get used to the parameters, speed, and power, but that is ok
How do you guys cut eg. 3mm acrylic glass?
Because of the depth, the focus of the laser should move down the material after each step.
Or do I set the focus on the level, the material is cut thru?