To overcome the challenges associated with CNC machining titanium, it is essential to use the right cutting tools. Here are some of the best options:

· Carbide tools with negative rake angles: Negative rake angles help to reduce cutting forces and prevent the tool from digging into the workpiece, which can help to mitigate work hardening.

· Sharp cutting edges: Sharp cutting edges are crucial for reducing cutting forces and improving surface finish.

· Coated tools: Coated tools, such as those with TiAlN or AlTiN coatings, can provide improved tool life and resistance to wear and galling.

· High-speed steel (HSS) tools: HSS tools can be used for roughing operations, but they may not be as durable as carbide tools for finishing cuts.

It is important to select the appropriate cutting tool based on the specific machining operation, workpiece geometry, and desired tolerances. Consulting with the tool manufacturer can help to ensure that you are using the best tool for the job.