Computerized Numerical Control
General Working Principle
CNC machining is a computer-controlled manufacturing method where programmed software controls complex machinery based on pre-determined movements. The wide range of machinery controlled by the software includes mills, turns, drills, and more.
Milling represents one of the most commonly used machining processes in subtractive manufacturing. This process uses of a rotary cutting tool with a geometrically-determined edge. Milling can be sub-divided into face milling and peripheral milling. Face milling is characterized by a vertical cutting axis and therefore mainly used for the processing of frontal areas and cavities. Peripheral milling, on the other hand, is used for deep slots and threads given its horizontal cutting axis.
The main advantage of milling lies in its compatibility with almost any material. Additionally, milling can produce highly-accurate parts with high standards regarding the surface finish. Another advantage is that milling is an established manufacturing process, resulting in great acceptance and knowledge among engineers.
Milling is particularly advantageous if the part requires many different features, e.g., drilled holes. Due to the high standards regarding accuracy and surface finish, resulting in high repeatability and comparably short lead times, milling is a very flexible manufacturing process from prototyping to series production.
Turning is a subtractive manufacturing process also known as lathing. Like milling, turning machines also operate with a geometrically determined cutting edge. Instead of the tool, the work piece is moving in a rotary way. Nevertheless, the cutting tool can move horizontally. Three of the most commonly used turning operations are step turning, facing, and threading.
The main advantage of turning lies in its compatibility with almost any material. Additionally, turning is capable of producing highly accurate parts with high standards regarding the surface finish. Another great advantage is that turning is an established manufacturing process, resulting in great acceptance and knowledge among engineers.
Turning is particularly beneficial if the shape of the part is centrally symmetric (i.e., resulting in conical end-parts). Turning has high accuracy and surface finish standards, resulting in high repeatability and comparably short lead times.
Drilling is a subtractive manufacturing process to produce holes in preparation for threading or as an end-use structure. For the drilling process bits with a geometrically determined cutting edge are used as tools.
CNC drilling is characterized by high reproducibility and its applicability to almost every material. The drilling processes has a high productivity, which can be further enhanced when the drilling machine is equipped with a tool turret.
Drilling is usually used when a hole in a solid material is needed. This can either be as pre-stage for an adjacent threading process or as end-use contour.