We are hard turning some circular knives (60 HRC), and are struggling to get a clean sharp edge, see attached pictures. We tried many different speeds, feeds, and depth of cuts. As well as using different CBN and ceramic cutting tips (V style, 0.8 rad), but whatever we do we can’t get the edge to clean up and not have any burrs.

Have you got any suggestions on how we can get a clean sharp edge? Is there a tool or method we are missing? We are using a Doosan Lynx CNC lathe.

Thanks

https://www.dropbox.com/s/zcdrl37hon...age1.jpeg?dl=0
https://www.dropbox.com/s/g5g5r3dalu...age2.jpeg?dl=0
https://www.dropbox.com/s/i75bjfkslv...age3.jpeg?dl=0