CNC Turning is mainly due to the rotation of the workpiece, through the required shape. When the tool moves along a parallel axis of rotation, the inner and outer cylinders can be obtained. The formation of the cone is the tool movement along the slash that intersects the axis. The rotating surface is formed on an imitation lathe or CNC lathe, where the control tool is fed along a curve. Another kind of rotating curved surface production, is the use of molding car knife, transverse feed. In addition, machining thread surface, end plane and eccentric axis can also be cut.