Computer Numerical Controlled (CNC) machines are being used in almost every kind of manufacturing process. With a CNC machine functions like program storage, tool offset and tool compensation, program-editing capability, various degree of computation, and the ability to send and receive data from a variety of sources, including remote locations, can be easily realized through an on-board computer. The computer can store multiple-segment programs, recalling them as needed for different parts.

CNC machines offer improved automation (many CNC machines can run unattended during their entire machining cycle), consistent and accurate workpieces, and flexibility: since these machines are run from programs, producing a different workpiece is almost as easy as loading a different program.

CNC Milling

CNC (Computer Numerical Control) milling is one of the most often used forms of all the CNC operations. Milling is used to do drilling, turning and sometimes even cutting. The machines are classified according to how many axes they have. In CNC milling, these axes are labeled x and y for vertical movement and z for horizontal movement. Standard CNC milling machines usually have four axes: Tables x, y and z and milling head z. A five-axis machine has an extra axis for the horizontal milling head. This gives extra flexibility to the machine.

The concept of using a mill to hone metal has been around for more than a century. Milling machines have taken this process a step farther by making it possible to machine the same type of piece over and over again to precise specifications. CNC milling machines allow users to create intricate patterns in metal materials like steel and aluminum. They are also useful for machining delicate parts such as pistons, valves, and other engine components. Because they are controlled by a computer, CNC milling machines offer a higher degree of accuracy than can be achieved with hand operated mills or lathes.

CNC Turning

With CNC Turning, the programmed CNC controller directs a lathe to machine an object either out of solid plastic or metal. Turning is a machining operation that produces cylindrical parts through the removal of material from the outside diameter of a workpiece to form a cylindrical surface. The surface may be straight (one continuous diameter), tapered or contoured (as a concentric but irregularly shaped surface).

In its basic form, Turning can be defined as the machining of an external surface:

• with the workpiece rotating
• with a single-point cutting tool
• with the cutting tool feeding parallel to the axis of the workpiece and at a distance that will remove the outer surface of the work

The three primary factors in any basic turning operation are speed, feed, and depth of cut. Other factors such as kind of material and type of tool have a large influence, of course, but these three are the ones the operator can change by adjusting the controls, right at the machine.