Implementation of High-Performance
Ceramic Tools for Machining Advanced Materials

Carbide's Hidden Limitation: A Scarce Raw Material

Tungsten, the key raw material in cemented carbide cutting tools, is available in less than 0.01% of the Earth's crust by mass, an increasingly relevant constraint for a cutting tool consumed at industrial scale. Full-ceramic silicon nitride tools are built instead from elements present in far greater abundance.

Rising tungsten prices add an economic argument on top of the resource-scarcity one: alternative cutting materials are increasingly a sensible choice not just for supply security, but for cost as well.

Abundance alone does not make a good cutting tool. The real question was whether a diamond-coated silicon nitride ceramic could actually perform in demanding, high-speed milling of carbon and glass fibre reinforced plastics, not just serve as a theoretical alternative on a data sheet.

Why Weight and Abundance Matter

Ceramic tools are around 78% lighter than cemented carbide, directly enabling higher achievable spindle speeds. Since cemented carbide tools run into rotational mass limits at high speed, this weight advantage is a genuine enabler for high-speed cutting (HSC) strategies rather than a marginal benefit.

Increasing cutting speed also paid off directly in the process: feed and feed-normal forces dropped as cutting speed rose, and the highest component edge quality over an extended milling path was recorded at the highest cutting speed tested, 1665 m/min.

A Different Way to Wear

Before wear ever entered the picture, the starting edge itself had to be controlled. Both the cutting-edge radius and the density of edge defects increased with coarser grinding grit used to prepare the ceramic edge, so a process-reliable, consistently small starting radius was only achievable with fine grinding grits.

Cemented carbide and ceramic tools wear in fundamentally different ways. The carbide tool develops a wear-related chamfer with a steadily increasing cutting-edge radius. The ceramic tool instead shows pronounced flank wear alongside a decreasing cutting-edge radius, forming a distinctive sawtooth-like edge profile with a tip spacing of roughly 10 to 20 micrometres.

Adding ultrasonic assistance showed a trade-off rather than a universal improvement: quality was lower than conventional milling over a short tool path, but higher than conventional milling once the path length increased, pointing to a benefit that only pays off over sustained tool use.