CNC Turning Explained

The word “turning” as applied to machining processes refers to the application of a cutting tool (commonly a non-rotary tool bit in the form of a simple single-point cutting tool) to cut a path by rotating or “turning” the piece being worked on while the tool remains fixed in place. Turning is generally only used to describe the creation of external surfaces by this cutting action, whereas the term “boring” is used for actions that work into the internal areas of a piece, such as the drilling of holes. These processes are, as a whole, thus often described as “turning and boring”, with “facing” sometimes also being used to describe work done on the face of a piece (which could otherwise technically fall into the turning or boring category).

In the past, turning was done manually, with a traditional lathe tool, relying solely on the cutter’s dexterity and expertise, along with the liberal application of time and trial and error. The lathe is believed to be one of the oldest tools used in machining history, and since its inception has been used in processes of four essential types: straight turning, taper turning, and profiling or external grooving, with each of these being employed to produce differently-shaped end results, with edges that are either straight, conical, curved, or grooved. Over time, people have come to use different cutting tools and angles for different materials, as they discovered which works best with the various unique textures and hardnesses of commonly-cut materials like wood, plastic, resin, and metal. Likewise, almost all turning done today is CNC turning, an automated form of turning crafted by machine rather than by hand.

How CNC Turning Benefits the Manufacturing Industry

CNC turning has many benefits versus traditional, manual turning:

• Much less waste (alternately called chips in North America, swarf in Britain, and turnings in some other regions) is generated by CNC turning, because the process is so precise, almost entirely removing human error. The path to cut is input into the CNC machine via a computer program, so that the cut can be made over and over with exact precision. Conversely, when each piece is cut by hand, there is the chance of error each time, with some whole pieces needing to be thrown out.
• CNC machines save time. They cut well, fast, without ever tiring as a human will, and can handle complex geometric shapes with ease. The use of CNC machines for not just turning, but a vast array of machining processes once done by hand, has allowed more goods to be produced more cheaply than ever before.
• CNC machines require minimal supervision. Someone who is trained to use CNC machines can generally program the machines, allow them to cut, sit back, and relax, unlike in the old days, when a great amount of human supervision was required to get each piece cut. This saves not only human labor, but cost to the manufacturer.