The spindle of a CNC vertical lathe is the core component of the machine tool. The requirements for the spindle are directly related to the performance, accuracy and stability of the machine tool. The following are some common requirements for CNC vertical lathe spindles:

1. Rigidity: The spindle must be rigid enough to resist cutting forces and other external loads to ensure that excessive deflection does not occur when processing large and heavy workpieces. The higher the rigidity, the better the accuracy and stability of the machine tool.

2. High speed: The spindle needs to have a high speed range to adapt to the processing needs of different types of workpieces and cutting materials. High rotation speed helps improve production efficiency and surface quality.

3. Accuracy: The machining accuracy of the spindle is directly related to the machining accuracy of the workpiece. The spindle should have a high-precision manufacturing process to ensure stable axial and radial accuracy during high-speed rotation.

4. Dynamic balance: The spindle must undergo precise dynamic balancing to prevent vibration and imbalance caused by high-speed rotation, thereby ensuring the stability of the tool and the surface quality of the workpiece.

5. Powerful drive system: The drive system of the spindle should be powerful enough to provide the required cutting power and ensure that the spindle can operate reliably under various working conditions.

6. Cooling system: In order to prevent the spindle from overheating, an effective cooling system needs to be designed. This can include internal cooling channels, coolant circulation systems, etc.

7. Automatic tool changing system: For multi-process or multi-tool processing applications, an automatic tool changing system may be integrated on the spindle to improve production efficiency.

8. Wear resistance: The surface coating or material selection of the spindle should have wear resistance to extend the spindle life and maintain accuracy.

9. Automatic oiling system: In order to ensure the lubrication of the spindle, an automatic oiling system can be used to ensure that the spindle is in good lubrication condition during high-speed operation.

10. Safety: The spindle should be designed to be safe and reliable, with protective measures to avoid accidents.

These requirements can be adjusted based on specific machining needs and machine tool design. Generally speaking, the spindle of a CNC vertical lathe needs to have high rigidity, high precision, high speed and reliable performance to meet diverse processing needs.