I've used hand held routers with 26000 rpm and single flute TCT for 2mm and that's cut fine. But I would say 300 rpm would be to slow. This might help you, scroll down about half way down the page. You'll see this

" Computerised trimming is a fully automatic milling process. It is extremely accurate and operates horizontally as well as vertically. The use of a vacuum-operated jig avoids vibration of the part ensuring a smooth cut. Standard high speed, two sided cutting routers with tungsten carbide tips are recommended, with a cutting speed of approximately 250 m/min at 25.000/30.000 RPM at a sheet thickness of 4 mm."

http://www.theplasticshop.co.uk/plas...sing_guide.pdf

Hope this helps. Mike