Took my 3mm thick FC plate to fablab where they have nice cnc router, wanted to cut out some arms for quadcopter frame. All went well but the router bits did not last long. I never used that sort of machine before, so i have few questions, first of what kind of bit i should use for CF ?

http://www.ebay.com/itm/Kent-10-Fishtail-3-0mm-Diameter-Carbide-Router-Bits-End-Mill-and-Engraving-Burrs-/291486224465?hash=item43ddeed051:g:emoAAOSw~OdVdGH-

you need to use a 'burr' if you in a hurry and cant wait for shipping , then use a tile cutting bit  ...