US Air Force commissioned MIT to develop the first "numerically controlled" machine in 1949. It was demonstrated in 1952. Motivation: To manufacture complex curved geometries in 2D or 3D was extremely expensive by mechanical means (which usually would require complex jigs to control the cutter motions). Most modern machine tool companies manufacture only NC or CNC machine tools. The dominant advantages of NC machines are: - Easier to program; easy storage of existing programs;

- Easy to change a program

- Avoids human errors

- NC machines are safer to operate

- Complex geometry is produced as cheaply as simple ones

- Usually generates closer tolerances than manually operated machines

System M3X-3S 3-Axis Control and Machine

Computer Numerical Control (CNC for short) is the process of having a computer controlling the operation of a machine. CNC machines typically replace (or work in conjunction with) some existing manufacturing process. Almost all operations performed with conventional machine tools are programmable with CNC machines. For instance, with CNC machines we can perform motion control in linear (along a straight line) or rotary (along a circular path) axes. The axes of any CNC machine are required for the purpose of causing the motions needed for the manufacturing process.

Having the computer control the machine is accomplished by a program that is written using NC code. A CNC program is a series of instructions written in sentence-like format. These statements are executed in sequential order, step by step. A special series of CNC words are used to communicate what the machine is intended to do. CNC words begin with letter addresses (like F for feedrate, S for spindle speed, and X, Y and Z for axis motion). When placed together in a logical method, a group of CNC words make up a command that resemble a sentence. For any given CNC machine type, there will only be about 40-50 words used on a regular basis.