What Are The Processes in CNC？

CNC machining core processes are divided into three major categories: cutting, forming, and special processing. These cover machining scenarios for rotary parts, complex surfaces, sheet-metal parts, and many other component types.

Cutting processes are the most widely applied and technically mature category in CNC machining. They primarily rely on the relative motion between the cutting tool and the workpiece to remove excess material, thereby achieving the required shape and dimensional accuracy.

(1) Turning

Horizontal/Vertical CNC Lathes: Mainly used for rotary parts such as shafts, discs, and sleeves. The spindle rotates the workpiece while the tool feeds to machine outer diameters, inner holes, end faces, threads, etc. CNC lathes are typically equipped with servo feed systems and turret tool posts, enabling automatic multi-tool changes. They are suitable for continuous processing of small-to-medium batches of multi-specification parts. Vertical lathes are better suited for large-diameter, short-length disc-type parts such as flanges and large bearing housings.

Turn-Mill Composite Machining: Integrates milling functions on the basis of turning, allowing multi-process machining of complex parts in a single setup and reducing setup errors. Turn-mill machines are usually equipped with live tool turrets and C-axis capability, enabling milling, drilling, and tapping operations simultaneously with turning. They are especially suitable for aerospace, medical device, and other industries that demand extremely high part consistency and accuracy, significantly shortening production cycles and reducing cumulative errors from multiple setups.

(2) Milling

Plane and Contour Milling: Used for machining planes, grooves, and 2D contour parts. It is a routine process for molds and hardware components. These operations typically use end mills or face mills, with XY-axis interpolation for contour tool paths. It is one of the highest-frequency basic processes in CNC machining.

Cavity and Surface Milling: Targeted at mold cavities and complex surface workpieces. Multi-axis simultaneous control realizes surface contour machining; five-axis simultaneous milling can machine spatial surfaces and is commonly used in aerospace and automotive mold fields. Five-axis simultaneous milling simultaneously controls tool position and orientation in space, avoiding tool interference and enabling complex free-form surfaces (such as impeller blades and automotive panel molds) that traditional three-axis machines cannot achieve.

Drilling and Boring: CNC drilling machines perform drilling and reaming; CNC boring machines are used for high-precision hole-system machining, with accuracy reaching IT5 or higher. Boring is particularly suitable for finishing large-diameter and deep-hole parts and is widely applied in hole-system machining of engine blocks and housing components, effectively ensuring coaxiality and positional accuracy between multiple holes.

(3) Grinding

Conventional Grinding: Includes cylindrical grinding, surface grinding, and internal grinding. Used for semi-finishing and finishing of precision parts to improve surface finish and dimensional accuracy. Grinding is usually the final process, removing residual stock from previous operations via high-speed grinding wheel rotation and micro-feeds to achieve mirror-level surface quality.

Form Grinding: Uses custom-shaped grinding wheels to machine special-contour parts such as cams and guideway surfaces. This process demands extremely high wheel-dressing accuracy and is typically performed with diamond rollers to dress the wheel profile, ensuring consistency and repeatability of the formed surfaces.

Forming processes mainly target sheet-metal and thin-wall structural parts. CNC equipment controls dies or tools to plastically deform the material rather than remove it by cutting.

(1) CNC Punching CNC punch presses perform punching, blanking, and shallow drawing of sheet-metal parts. They are commonly used for mass production of home-appliance and automotive sheet-metal components. CNC punch presses are usually equipped with turret tool magazines that automatically switch multiple dies to complete different operations. They are especially suitable for multi-hole, multi-shape combination sheet-metal parts such as distribution-box panels and air-conditioner housings.

(2) CNC Bending CNC press brakes precisely control bending angle and position to form sheet-metal angles, with accuracy reaching 卤0.1掳. They are typically equipped with automatic back-gauge positioning systems and angle-detection sensors that real-time compensate for material spring-back, ensuring consistent bending angles in batch production. Widely applied to chassis cabinets, sheet-metal brackets, and similar products.

(3) CNC Broaching CNC broaching machines machine high-precision slots such as keyways and splines. Efficiency and consistency are superior to manual broaching. Broaching uses multi-tooth broaches that cut tooth by tooth; a single stroke completes both roughing and finishing of the slot profile. Especially suitable for high-efficiency machining of standardized features such as keyways and spline holes in mass production.

Special processes are non-traditional material-removal methods used for high-hardness, high-brittleness materials or complex precision structures. They serve as important supplements to conventional cutting processes.

(1) Electrical Discharge Machining (EDM)

Sinker EDM (Die-Sinking EDM): Uses pulsed electrical discharge between electrode and workpiece to erode metal. Suitable for hard-brittle materials, complex mold cavities, and workpieces that cannot be machined by conventional cutting. Because the electrode and workpiece do not make direct contact, machining is independent of material hardness and is particularly suitable for precision cavity machining of hardened steel, cemented carbide, and other difficult-to-cut materials. Widely used in injection-mold and die-casting mold manufacturing.

CNC Wire EDM: Uses a moving molybdenum or copper wire as the electrode to cut 2D contour parts. Commonly applied to mold templates and precision hardware. Wire EDM is divided into high-speed (fast-wire) and low-speed (slow-wire) types; slow-wire EDM offers higher accuracy and better surface quality and is frequently used for precision stamping dies and irregular-hole parts.

(2) Laser CNC Processing

Laser Cutting: High-power laser melts/vaporizes material to cut metal and non-metal sheets. High cutting accuracy and small heat distortion. Advantages include narrow kerf, high cutting speed, and wide material adaptability. Widely used in sheet-metal processing, advertising signs, and precision-part blanking, especially suitable for rapid cutting of complex contours and fine patterns.

Laser Welding and Marking: Integrated into CNC equipment for part welding and identification. Laser welding features small heat-affected zones and low welding distortion, suitable for precision parts and thin-wall structures. Laser marking is commonly used for permanent marking of serial numbers, QR codes, and brand logos, widely applied in electronics, medical, and automotive component industries.

(3) CNC Waterjet Cutting High-pressure water mixed with abrasive cuts various materials with no heat distortion. Suitable for heat-sensitive materials such as glass and stone. Cutting pressure can reach hundreds of MPa and can cut almost all materials including metals, stone, glass, and composites. The process generates no heat-affected zone and is particularly suitable for precision parts sensitive to temperature or prone to thermal deformation. Increasingly applied in aerospace and architectural decoration fields.