There are many new and innovative prototyping processes in use today, including 3D printing. But CNC machining is still the most common way to mass produce parts. There are several known methods of CNC machining hand models: 1. Turning Turning simply involves firmly clamping the workpiece to a rotating plate or mandrel. As the workpiece rotates, the cutting tool is held against it in a fixture mounted on a moving slide. The slide can be moved up and down the length of the workpiece, as well as closer to or further away from the centerline, this simple operation is ideal for removing large quantities of material quickly. In addition, the drill bit mounted on the tailstock of the lathe can drill precise holes; the lathe is used to form concentric shapes on the outer circumference of circular parts; grooves, ring grooves, stepped shoulders, internal and external threads, cylinders are made on the lathe Body and Shaft - Many circular or circular features. 2. Milling Milling is fundamentally different in that the workpiece remains stationary and the cutting tool rotates on a spindle. The workpiece is usually held horizontally in a machine vise, mounted on a table that moves in the X and Y directions. The spindle can hold various tools and move in X, Y and Z axes. Milling cutters are used to make squares/flats, notches, chamfers, channels, profiles, keyways and other features that depend on precise cut angles. As with all metalworking operations, cutting fluids are used to cool the workpiece and cutting tools, to lubricate, and to flush away metal particles or swarf. 3. Grinding Grinding to create very flat surfaces on metal parts is important for many applications, and the best way to create such precise surfaces is with a grinding machine. Grinders are rotating discs covered with abrasive grit of a specific roughness. The workpiece is mounted on the table and moved laterally back and forth on a sliding table below the wheel, or sometimes held steady while the wheel moves. Depending on the material being ground, different types of abrasives are used. The thermal and mechanical stresses of the grinding process can adversely affect the workpiece, so tool speed and temperature must be carefully controlled. 4. EDM Solid EDM is used to make dimples, holes and square features inside hardened tool steel that would be difficult, if not impossible, to make any other way. It is commonly used in molds for plastic injection and pressure molding, and rarely in the finished part itself. EDM is also used to make textured surfaces or debossed (debossed) letters and logos on molds. 5. Wire cutting Wire cutting uses copper wire as a conductor of high voltage charges. As the conductor is steadily corroded during the cutting process, new wire is fed from the spool. This technique requires a pass and cannot be used for blind vias. Wire EDM is used on thick, hardened tool steels to create round or semi-circular features that would be very difficult to make with conventional cutting tools. 6. Optical grinding Optical grinding we only discuss machining metals, but CNC machining is also used to make special optics from glass or plastic. Optics require very fine surfaces with very tight tolerances, so specialized grinding equipment is used that rotates the grinding wheel relative to the surface while rotating on multiple axes. By using the manufacturing and processing methods of the above several prototype models, the quality of CNC products processed by many prototype processing factories has been improved rapidly, and thus they have gone to the world.