Milling is a common cold working method for metals. Unlike turning, in milling, the cutting tool rotates at high speed driven by the spindle, while the workpiece remains relatively stationary.
Milling is a machining method that uses a rotating multi-edged cutting tool (end mill) to cut a workpiece, removing material and obtaining the desired shape, size, and surface quality. Its basic principle is: by rotating the end mill mounted on the spindle (main motion), it intermittently cuts a workpiece that is relatively stationary or performing linear feed motion (feed motion).
This process can not only machine workpiece surfaces into planes and curved surfaces, but also perform various machining operations such as drilling and grooving. It is one of the most commonly used methods in metal cutting, mainly used to machine various planes, grooves, and shaped surfaces, and can also be used for drilling and reaming.
Based on the spindle direction where the cutting tool is mounted, common milling machines can be divided into horizontal milling machines, vertical milling machines, and gantry milling machines with a portal frame.
Based on the degree of automation and control method, milling can be mainly divided into: general milling, which is operated and judged manually by the operator and is suitable for occasions requiring fine machining; NC/CNC milling, which achieves automated operation through computer numerical control (CNC) and is suitable for machining complex shapes; machining centers, which are CNC machine tools with multiple spindles and multi-axis composite functions that can continuously perform various cutting operations such as milling and drilling; and NC gear machining machines, which are CNC equipment specifically used for the manufacturing of various types of gears.