If you have any trouble with melting while cutting Plexiglass or Lexan (sawing, drilling, milling, turning, etc.), just spray the cut and the tool with WD-40, 409, or just plain water in a spray bottle while you are cutting. It will cool the cutting tool and the material and leave a nice smooth cut. I mostly use WD-40 on the band saw and on the lathe just to keep from spraying water on the machine, but I have used all three with very good success and none of the three have any deleterious effect on the Plexiglass.