CNC machines, Computer Numerical Control is the automated control of machining tools of drilling, boring milling and lathing.  A machine alters a blank piece of material (metal, plastic, wood, ceramic, or composite) to meet precise specifications by following programmed instructions and without a manual operator. Cutting programs and instructions are delivered to an CNC machine in the form of graphical computer-aided design (CAD) files, which are transformed into a sequential program of machine control instructions, and then executed.