Most CNC workshops cut carbon fiber sheets using millers and the routerbits are very important for them to yield good quality cutting edges and tolerance. Of course, it helps a lot for the cutting efficiency if the routerbits are diamond coated and workers don't need to stop the machine to replace the new routerbits. Shanghai Lijindustry introduced  the really good quality routerbits for our cuting servies and also offer them worldwide since 2015. The shank diameter is 3.175mm and cutting diameters range from 0.6 to 2.4mm. We are sure you will like the routerbits once you try it.