Five-axis linkage machining centers are generally divided into vertical machining centers and horizontal machining centers ~ vertical five-axis machining centers. There are two ways for the rotary axis of machining centers. One is the table rotary axis. The worktable set on the bed can rotate around the X axis, which is defined as the A axis. The A axis generally works from +30 degrees to -120 degrees. There is also a rotary table in the middle of the worktable, which revolves around the Z axis, which is defined as the C axis, and the C axis rotates 360 degrees. In this way, through the combination of A-axis and C-axis, except for the bottom surface of the workpiece fixed on the worktable, the other five surfaces can be processed by the vertical spindle. The minimum index value of A-axis and C-axis is generally 0.001 degree, so that the workpiece can be subdivided into any angle, and inclined surface, inclined hole, etc. can be processed. If the A-axis and C-axis are linked with the XYZ three linear axes, they can process complex space surfaces. The other is to rely on the rotation of the vertical spindle head. The front end of the main shaft is a revolving head that can circle the Z axis 360 degrees to become the C axis. The revolving head also has an A axis that can rotate around the X axis, which can generally reach more than ±90 degrees to achieve the same function as above. The advantage of this setting method is that the spindle processing is very flexible, the worktable can also be designed to be very large, and the huge fuselage and huge engine shell of the passenger aircraft can be processed on this type of machining center.