What is CNC machining?

In the early stages, there were two versions: NC (Numerical Control), representing the older, original numerical control technology; and CNC (Computerized Numerical Control), the newer version and the preferred abbreviation for numerical control today.

While an NC system might technically be a CNC system, the term CNC never refers to the older numerical control technology. Early numerical control systems relied on hardware circuitry—known as "Hard NC." From the 1970s onwards, hardware components were gradually replaced by dedicated computers, giving rise to Computerized Numerical Control (CNC) systems. These systems typically utilize dedicated computers equipped with interface circuitry capable of controlling the operations of multiple pieces of numerical control equipment. Consequently, modern numerical control is almost exclusively CNC, and the term "NC" is rarely used anymore.

Numerical control machining offers the following advantages:

① It significantly reduces the need for tooling; complex parts do not require complex fixtures. Modifying a part's shape or dimensions simply requires altering the machining program, making the technology ideal for new product development and design modifications.

② It ensures stable machining quality with high precision and repeatability, meeting the rigorous manufacturing requirements of the aerospace industry.

③ It offers high production efficiency for multi-variety, small-batch manufacturing. It reduces time spent on production preparation, machine setup, and in-process inspections, while also shortening actual cutting time through the use of optimal cutting parameters.

④ It enables the machining of complex surfaces that are difficult to process using conventional methods, including areas that are not directly visible. The disadvantages of numerical control machining include high equipment costs and the requirement for highly skilled maintenance personnel. The parameters controlled typically include mechanical variables such as position, angle, and speed, as well as switching signals related to the flow of mechanical energy.

The emergence of numerical control relied on the development of data carriers and binary data processing. Interchangeable data carriers in the form of perforated metal sheets appeared in 1908; control systems using paper-based data carriers with auxiliary functions were invented in the late 19th century; and in 1938, Claude Shannon conducted research on high-speed data processing and transmission at MIT, laying the foundation for modern computers, including CNC systems.

Numerical control technology evolved in close conjunction with machine tool control. The first CNC machine tool was unveiled in 1952 (a collaborative effort between Parsons and MIT); this marked a watershed moment in the history of the global machinery industry and propelled the advancement of automation. Numerical control technology—also known as Computerized Numerical Control (CNC)—is a method that utilizes computers to implement digital program control. It employs a computer to execute control functions regarding equipment motion trajectories and the operational timing logic of peripherals, based on pre-stored control programs. By replacing traditional hardware-based logic circuits with computer systems, various control functions—such as the storage, processing, and calculation of input commands, as well as logical decision-making—are realized through software; the resulting micro-instructions are then transmitted to servo drive units to operate motors or hydraulic actuators, thereby driving the equipment.