Quote Originally Posted by BillTodd View Post
Could you use the DVD mechanism's focus servo ? (i.e. it already has a beam splitter and monitor diodes)
Not sure to be honest, Don't think the DVD burner runs the diodes that high (so little heatsink may not be good enough, though possible on a lightscribe?

There also designed to be a couple of mill off the surface which could presesnt quite a problem.

Once your diodes in your Z axis and focused to produce the smallest spot size at 50% z axis travel, you can then jog your Z up and down to focus.

The beam created with those Axiz 12 x 30mm lens looks like an hour glass, At the point where the two sides of this hour glass cross is where your material surface should be.

Like........

Ignore the steering mirror.

Michael.