Well what do you want to know about DVD laser burning?

You could just buy a 300mw DVD diode in a 12x30 mm housing with lens and driver board off Ebay for about £30, Seller I think is in South Korea but had a good track record with UK customers.

I made a mount to hold the diode where my spindle would usually go, The driver board I used needed a 6v Regulated supply so I just gave it 6v via a regulator switched via a Solid state relay driven directly by the parallel port.

I then wrote a simple script that swapped out Z moves in the G Code created by Cad software for M codes to turn laser on and off, The etching of a baby on some wood was done with a 180mw 635nm DVD laser diode.

Focusing the laser takes a little trial and error, But I got a spot size down to 0.07mm, Even 180mw at a spot size that small is a fair amount of energy.

Please feel free to ask me any questions as I know I ramble and talk shit sometimes.

Michael.