Milling is a machining process that utilizes a rotating multi-point cutting tool to remove material from a workpiece, recognized for its high efficiency and precision in manufacturing. During operation, the milling cutter rotates at high speed to perform the primary cutting motion, while the workpiece moves along a predetermined path to supply the feed motion. In certain configurations, the workpiece may remain stationary, requiring the rotating cutter to simultaneously execute both the primary and feed motions. Milling is widely applied to process various materials, including metals, plastics, and composites, making it essential for producing complex geometries and achieving tight dimensional accuracy.

Depending on the machine tool structure and specific processing requirements, milling machines are mainly categorized into horizontal mills, vertical mills, and large gantry mills. Horizontal milling machines feature a horizontally oriented spindle and are suitable for heavy-duty cutting and multi-face machining operations. Vertical milling machines, with a vertically aligned spindle, are more adept at face milling, cavity machining, and drilling. Gantry mills are commonly used for high-precision machining of oversized workpieces, frequently in industries such as aerospace and energy equipment. With advancements in CNC technology, conventional manual milling machines have largely been replaced by CNC milling machines, which employ computer programming to automate the machining process. This shift has significantly enhanced productivity, consistency, and the capability to produce complex contours, precision threads, gears, and mold cavities with exceptional accuracy.

Owing to its versatility and adaptability, milling is widely employed in the manufacturing of various components, including but not limited to flat surfaces, steps, slots, keyways, T-slots, formed surfaces (e.g., turbine blades and spiral bevel gears), and specialized mold profiles. Furthermore, in the context of smart manufacturing, milling technology is often integrated with CAD/CAM systems to enable seamless transition from digital 3D models to finished products.

Given its broad applicability and continuous improvements in cutting tool technology and CNC systems, milling remains an indispensable core machining method in modern manufacturing.