"Light Curtains" and pressure sensitive pads are the type of safety features you see on some of the larger CNC's used for architectural mill work and the like (such as Biesse).
Most guitar makers use Fadals or Haas and these are usually configured with an enclosure on at least 4 sides.
I built a quick and dirty enclosure around my K2...mainly to keep the dust down, but also to catch the errant part that breaks free from the double stick tape (already have one little "oops" window).
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Rick - I didn't mean to knock big machines. If you are running a lot of production work or are running sheet goods, then by all means..that's not a bad option (I was thinking more for the average hobbyist). I was just trying to point out that by making a machine that runs across a greater span, it is harder for the manufacturer to ensure good repeatability & accuracy. As with everything...there are many ways to skin a cat.
