Reciprocating Laser Cutter

On Saturday afternoons, like any good grad student, I visit my parents place to do my laundry. While it's spinning around, my dad and I usually get up to some neat projects, and this is what we worked on this week.

I've had an idea for a while that one might be able to build an inexpensive laser cutter using a 1 Watt IR laser diode, as opposed to the larger 20-100 Watt CO2 tubes traditionally in something like an Epilog laser cutter, using a bit of a trick. Traditionally laser cutters have a lot of power, and (to my knowledge) are generally fixed focus, meaning that the focal point -- the hottest portion of the cutting beam -- stays at a fixed depth relative to the material that you're cutting. This is an experiment in dynamically varying the depth of the focal point through the material at runtime, such that you create a boring, "reciprocating laser cutter" or reciprocating laser mill.

This is an offshoot of my Open SLS 3D printer project, and was constructed using the same las