Four-axis linkage, five-axis linkage generally refers to the machining center, CNC milling machine or engraving machine control system linkage control axis. Four-axis linkage must first have four controllable axes, and four axes can be simultaneously interpolated motion control, that is, four axes can be realized at the same time linkage control, this simultaneous linkage when the speed of movement is the speed of the synthesis, not the respective motion control, is a point in space through the simultaneous movement of the four axes to reach the space of the other point, from the starting point of the simultaneous movement to the end point of the same time to stop the intermediate axes of the movement of the speed is based on the programmed speed through the controller. The speed of each axis is synthesized internally by the controller's motion interpolation algorithm according to the programmed speed. For four-axis machining centers, it is X, Y, Z axis plus a rotary axis A (can also be B or C axis, A, B and C axes are defined to correspond to the axis rotating around the X, Y and Z axes respectively, generally this fourth axis is the axis rotating around the X-axis A axis or axis rotating around the Y-axis B axis, which depends on the actual machine tool installation of the fourth axis of the form of the form of the fourth axis), and the fourth axis not only can alone (And this fourth axis not only can move alone but also can be respectively and other one axis or two axes or these four axes at the same time linkage. Some machine tools it is four axes, but it can only be a separate movement, only as an indexing axis, that is, after rotating to an angle to stop and lock the axis is not involved in cutting, only for indexing, only kind of only called four-axis three linkage. The same four-axis linkage machine can be more than the total number of four axes, it can have five axes or more, but its maximum number of linked axes is four axes.
Five-axis machining refers to a machine tool with at least five axes (three linear and two rotary), and can be under the control of a computer numerical control (CNC) system at the same time coordinated movement for processing. Linkage is a CNC machine tool axis according to a certain speed at the same time to a set point, five-axis linkage is five axes can be. Five-axis linkage CNC machine tool is a high-tech, high precision machine tools dedicated to the processing of complex surfaces, this machine tool system for a country's aviation, aerospace, military, scientific research, precision instruments, high-precision medical equipment and other industries, has a significant impact.