Ceramics are easiest to machine in the “green” or unfired state. They can be machined with conventional tooling (usually coated tungsten carbide or diamond tooling) in the bisque or semi-fired state. Full-fired ceramics must be machined with diamond tooling, or by methods such as ultrasonic machining, laser machining or abrasive waterjet cutting.
As ceramics are porous, they are commonly machined dry.
Cutting forces should be directed in the compressive direction.
Clamping should avoid flexural or tensile stresses.
“Ceramic Machining: Assessment of Current Practice and Research Needs in the United States.” NIST.Gov, National Institute of Standards and Technology, June 1992, https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication834.pdf.