What are the reasons for the malfunction of the electric spindle? How to solve it?

1. Significant noise and vibration

Cause analysis: Improper assembly of the spindle can cause damage to bearings or other components, resulting in low bearing accuracy or poor holding force, poor coaxiality between the stator and rotor, uneven air gap between the stator and rotor, low manufacturing accuracy of spindle components or deformation and loss of balance accuracy after long-term use, insufficient preload force or improper installation of springs, or even breakage, fracture or poor contact of rotor cage bars, as well as poor rigidity and accuracy of grinding wheel connecting rods.

Solution: Select good bearings, calibrate the coaxiality of the positive and rotor, check the accuracy of the main parts such as the casing, shaft, rotor, and cover, increase the preload force, reassemble the electric spindle, and choose a rigid and high-precision grinding wheel connecting rod to ensure the normal and stable operation of the electric spindle.

2. Difficult to start

Cause analysis: The power plug is not properly plugged in, the contact is poor or not connected, the power supply is insufficient or not matched with the electric spindle, the frequency converter startup protection is not adjusted to the optimal value, the power supply is out of phase or the contactor is poorly connected, all of which can cause difficulties in starting the electric spindle. Excessive pre tension applied to bearings and mutual friction between components in the electric spindle can also cause difficulty in starting. In most cases, the reasons for its difficulty in starting are: incorrect connection of the motor stator leads in the electric spindle, too small air gap between the stator and rotor, and damage to the stator winding.

Solution: First check the voltage, current, and power of the power supply, check if the power condition is normal, readjust the frequency converter according to the electrical parameters of the electric spindle, and then check the insulation of the stator winding to ground and the balance of the three-phase winding. Once a fault is found, it should be repaired immediately. If the air gap between the stator and rotor is too small, grind the outer diameter of the rotor to maintain the gap between the stator and rotor at the design value. If there is friction between parts, grind the outer diameter of the parts to ensure sufficient clearance between them. By changing the given preload value, the starting conditions of the electric spindle can also be improved. So when the electric spindle has difficulty starting, specific solutions should be found for the equipment.

Poor machining accuracy, cause analysis, poor bearing accuracy, poor spindle accuracy, loss of spindle accuracy due to human damage or long-term work, loose fit between front bearing seat and bearing, insufficient preload or stuck parts, loose front and rear nuts, shaft movement, poor quality of grinding wheel connecting rod. The solution is to choose a better bearing, reassemble it, coat it with hard chrome, re grind the seat hole and spindle to the required accuracy, increase the pre tightening force, lock the front and rear nuts, use anti loosening set screws for locking, and choose a rigid and high-precision grinding wheel connecting rod.

3. Slow or unstable speed

Cause analysis: The power supply voltage is too low, does not match the electrical parameters, has low power, and the rotor cage bar is broken or has poor contact.

Solution: First check whether the power output, frequency, voltage, and power match the electric spindle. If the power of the electric spindle is too low, choose an electric spindle with higher power that meets the working conditions, check the quality of the cage bars, and choose an electric spindle with larger capacity.

4. Continuous burning of bearings

Cause analysis: Poor lubrication, high speed, insufficient or excessive preload, and excessive bearing load.

Solution: Replace the lubricating grease or check the quality of the oil mist, check the oil supply in the oil circuit, measure the speed, adjust the frequency converter to ensure the normal operation of the electric spindle, and check and adjust the preload force to reach the optimal value.

5. Spindle heating

Cause analysis: The cooling water channel is not unobstructed, the selected bearing accuracy is low, the fit is too tight, the bearing is installed backwards or not in place, the preload is too high, the power supply voltage is too high, and the grinding feed rate is too large.

Solution: Check and clear the waterway, select a better bearing, measure its size, re select, reduce the pre tension appropriately, reassemble, check the air gap and current value between the stator and rotor, check the power supply voltage, and control the grinding feed rate.

6. The temperature of the stator winding is too high

Cause analysis: The power supply is out of phase or the voltage is too high, the rotor cage bar is broken, the water jacket is leaking, and the waterproof labyrinth seal at the front end of the grease lubricated electric spindle is not good.

Solution: Measure and adjust the voltage to make the electric spindle meet the requirements, check the quality of the cage bars, replace the rotor in a timely manner, check for water leakage, and replace the front end of the electric spindle with a structure with good sealing performance, such as air seal or multiple labyrinth seal.