Cutting plastic can be a challenge. The challenge is in keeping the plastic from melting and gumming up the cutter and ruining the work piece. You must make sure you get a bit designed for plastic, usually up-cut, single flute; O-Flute bits are used. Onsrud makes them but they can be pricy. I have a couple of less expensive O-flute bits on the way and I will give you my thoughts on these bits once I use them.