Developments in polycrystalline diamond (PCD) and cubic boron nitride (CBN) have allowed these materials to improve in ways that make them more versatile and cost-effective. Meanwhile, the machining speed and tool life of these tools continue to take machining processes to levels of performance where carbide cannot go.
Through long tool life and fast cutting parameters, the tools increase machine capacity by reducing the frequency of tool replacements and allowing machines to make parts at a greater rate. Meanwhile, the tooling increasingly figures into expert solutions tailored to more demanding applications in various industries.
Source: The New Rules of Cutting Tools - Rule #3: Diamond Shouldn't Be Rare