Tech Tips for Machining Hardened Materials with Ceramic and CeramiX

Here are some simple quick tips when you are machining machining hard materials. 

• As material hardness goes up the SFM goes down.
• Use the strongest possible insert shape to maximize insert strength.
• Ceramic is a hard material therefore, the insert needs some edge preparation in order to withstand cutting forces and optimize performance.
• Utilize positive geometries for close tolerances or thin-walled parts.
• If multiple passes are required with one edge, vary the DOC to move the wear on the insert edge and improve tool life.
• If you encounter chatter, increase your feed rate. Heavy chatter is often a sign of the tooling being above centerline or there is too much toolholder overhang. The machine, part and tooling set-up must be rigid.

When you're considering inserts from NTK Cutting Tools for hard turning, take a look at the grades and styles.

1.  Light edge preps T styles ( T-land:  T0425  & T0525)
2.  Heavy edge preps:  Z and S style ( T-land and honed edge: Z0820, Z0825, S0820, S0825) or  J, P, and Q style (Double Chamfered and Honed edge: P4815,  P8015, Q8015)

Hard Turning Speed SFM chart based upon a material's Shore Hardness.. As the hardness increases the SFM decreases.

Some good rules of thumb for Hard Turning: The IPR Feed Rate is based upon ceramic insert nose radius and Depth of Cut (DOC)

Best choice of ceramic insert grades for use in hard turning from NTK