The material rotates over a spindle. A grinding or carving tool can make the shape as it turns. CNC Lathes are used to produce symmetrical objects like spheres, cones, or cylinders. Quite a few CNC machines are multi-function and Mix all sorts of cutting. The examples have been pretty interesting, https://industrial-machining-tech02232.blogdomago.com/38119250/a-secret-weapon-for-sheet-metal-part-manufacturing