1. Machine bed and worktable: The bed is the foundation of a five axis machining center and is generally made of high-quality cast iron or steel structure to ensure its rigidity and stability. Workbenches generally include fixed workbenches and mobile workbenches, used for clamping workpieces.

2. Spindle head: The spindle head is one of the key parts of a five axis machining center, and generally uses a high-precision and high rigidity structure to complete high-speed and high-precision machining. The movement of the spindle head can be carried out on three coordinate axes, and can rotate around two axes together.

3. Numerical Control System: The numerical control system is the control core of the five axis machining center, capable of completing high-precision and high-speed machining. Generally, high-quality CNC systems such as FANUC are selected.

4. Tool magazine and tool changing equipment: The tool magazine is another important part of the five axis machining center, used to store various tools required during the machining process. The tool changing equipment can complete automatic tool changing and improve processing power.

5. Drive system: The drive system is another critical part of the five axis machining center, used to complete the movement of each axis of the machine tool. Generally, high-precision and high rigidity servo motors and screw drive systems are selected.

6. Protective equipment: Five axis machining centers are generally equipped with protective equipment for maintaining the operator and the machine tool itself. Including protective covers, guardrails, etc.

In summary, the structural composition of a five axis machining center includes the machine bed and worktable, spindle head, CNC system, tool magazine and tool changing equipment, drive system, and protective equipment. The reasonable design and cooperation of these parts can achieve efficient and high-precision machining.