The spindle is the power auxiliary device of the CNC machining center, which drives the workpiece to rotate and process the rotating workpiece. High speed and high-precision machining of CNC machining center spindles is an important guarantee, so the maintenance methods and skills for CNC machine tool spindle faults are also knowledge that CNC machining center operators and maintenance personnel need to master.

We know that due to the different motion modes and states of the spindle, CNC machining centers can be divided into vertical machining centers and horizontal machining centers. Different types of CNC machining centers use different spindle types, but generally speaking, the spindle system of CNC machine tools can be divided into main drive spindles with variable speed gears, main drive spindles driven by belts, and spindles driven by dual motors and integrated with motors and spindles according to the different transmission systems.

Currently, the commonly used spindle is one that integrates an electric motor with the main spindle. This type of spindle is usually called an electric spindle, and the electric motor itself is the spindle. This main transmission method greatly simplifies the structure of the spindle housing and spindle, improves the stiffness of the spindle components, but the output torque of the spindle is relatively small, and the heating of the motor has a significant impact on the spindle. Many spindles of CNC grinders use this method, and the speed can reach tens of thousands of revolutions per minute. Usually, the spindle motor is cooled by a circulating water cooling system.

Common faults of electric spindle

1. Overload

Reason for malfunction: excessive cutting amount, frequent forward and reverse rotation, spindle motor malfunction, spindle drive device malfunction.

2. The spindle does not rotate

Reason for malfunction: spindle drive device malfunction, CNC device unable to output speed signal, spindle motor malfunction, spindle drive device malfunction, transmission belt breakage.

3. Deviation between spindle speed and command value

Reason for malfunction: motor overload, problem with spindle speed command output from CNC system, malfunction of speed measuring device or disconnection of speed feedback signal.

4. Abnormal noise and vibration of the spindle

Reason for malfunction: It usually occurs during deceleration when there is a problem with the spindle drive device, such as a regeneration circuit failure in the AC drive.