CNC milling is also known as computer numerical control milling, and it is the most common form of CNC. CNC mills are capable of performing functions of drilling and turning. CNC mills are classified based upon the number of axes that they possess. Axes are labeled as x and y for their horizontal movement and z for their vertical movement. A manual standard light-duty mill is usually assumed to have four axes: table x, table y, table z, and milling head z. The number of axes that a milling machine has is a common subject during casual “shop talk” and it is usually interpreted in different ways. CNC milling machines are typically programmed using a set of commands referred to as G-codes. G-codes represent specific and exact CNC functions in alphanumeric format.