Tinker/Grad Student extraordinaire Peter Jansen describes a simple/clever trick to use a low-power 1W laser diode to plow through thick material typically tackled by only larger systems. The technique involves moving the laser up/down on the Z-axis to focus the beam at different depths as it eats way material. Peter's test system is a 3-axis machine constructed of parts from old DVD burners and printers. While there, go ahead and dig through the RepRap site and learn about the wonderful world of DIY 3D printing.