Hard Turning a Clean Sharp Edge

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

Hi, I would think that hard turning to a fine edge is physically impossible due to tool pressure and a negative tool cutting edge...…...I think you would need to second op grind the edge to get a sharp finish.
Ian.

Quote:

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Originally Posted by handlewanker

Hi, I would think that hard turning to a fine edge is physically impossible due to tool pressure and a negative tool cutting edge...…...I think you would need to second op grind the edge to get a sharp finish.
Ian.

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Yup, what Ian said.