I came across a Indiegogo campaign for a laser cutter add on suitable for 3d printers and mills. It claims to cut 3/16 in acrylic and timber. If it does what it says then I think it's good value for $220 especially as he's offering to make custom mounts for any printer or mill. https://www.indiegogo.com/projects/l-cheapo-laser-cutter-attachment The only down side it see to this on a mill is lack of fume extraction. The upside is that now it's met its funding goal the designer is planning to release details of the laser cutter attachment on his website.