I regularly cut acrylic with my mill, and the best way I've found so far to support the material (so it does not lift/flap during cutting) is to screw it down as much as possible. But that gets tedious and time-consuming, even with a powered screwdriver.

For larger pieces, I also slide a strip of aluminum pressed onto the acrylic, and close to the cutting bit, but that's not exactly safe.

I know of the existence of vacuum tables, but I've never seen one in action, and I wonder how I would not cut into the vacuum table, when I need to cut all the way through the acrylic. So what other techniques are there?

Pic beow is with a cell-phone, but you can see the #6 screws holding the sheet at regular intervals.

Thanks,
-Neil.