One of the most common malfunctions of molecular pump units is the failure to meet the required vacuum level, manifested by the vacuum gauge consistently displaying values higher than the target value, making it impossible to achieve the high vacuum state required by the process. There are three main reasons for this problem: firstly, the aging or damage of the sealing components, such as the cracking of the flange sealing ring due to long-term high and low temperature alternation, leading to air leakage; Secondly, there is blockage in the air inlet or pipeline, which hinders the flow of air due to the accumulation of dust and process residue; The third reason is the performance degradation of the molecular pump itself, rotor blade wear, or insufficient motor speed. When diagnosing, a helium mass spectrometer leak detector can be used to test the sealing surface first. If helium leakage is found, the sealing component should be replaced; Recheck the intake pipe and blow or disassemble the blockage with compressed air; If there are no abnormalities in the first two items, it is necessary to check the motor speed and replace the rotor or motor if necessary.

Abnormal noise and vibration are also its high-frequency faults, which can produce harsh sounds or severe shaking of the machine during operation, not only affecting the service life of the equipment, but also potentially damaging related components. The root cause of the malfunction is often mechanical imbalance, such as rotor dynamic balance being disrupted, bearing wear or insufficient lubrication, or loose connection between the pump unit and the base. The diagnostic steps are as follows: First, stop the machine and check the connecting bolts, then tighten them with a torque wrench to the standard torque; Next, disassemble the pump body and observe whether there are scratches or wear on the bearing balls. If there are any problems, replace them immediately and add special high-temperature lubricating grease; If the bearing is normal, the rotor needs to be dynamically balanced and calibrated to ensure that its center of gravity remains stable during rotation.

In addition, motor overload tripping faults are also common, where the equipment suddenly stops running and the overload protection switch in the distribution box is disconnected. This fault is usually caused by excessive load, such as foreign objects entering the pump chamber and getting stuck in the rotor, poor heat dissipation of the motor causing high temperature, or unstable power supply voltage. When troubleshooting, first cut off the power and manually rotate the rotor. If there is any jamming, disassemble the pump body to remove foreign objects; Check whether the motor cooling fan is damaged, whether the cooling channel is blocked, and clean or replace the components in a timely manner; At the same time, use a multimeter to check the power supply voltage and ensure that it is within the rated voltage range of the equipment. If necessary, install a voltage regulator.

Its fault diagnosis and troubleshooting need to follow the principle of "observing the phenomenon first, analyzing the cause, and finally handling it accurately". At the same time, regular preventive maintenance should be carried out, such as cleaning the sealing surface, checking the bearing status, calibrating motor parameters, etc., in order to minimize the occurrence of faults and ensure the long-term stable operation of the equipment, providing reliable vacuum environment support for high-precision production and experiments.