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Fault and Maintenance of CNC Machine Servo System
Computer numerical control (CNC) machine tool servo system is the core and the most complex system of CNC machine, which occupies an important position in the CNC machine system, and its performance directly affects the machining accuracy and economic benefit of the CNC machine tool. With the wide application of CNC machine tools, CNC machine tool servo system has become the main focus of maintenance work.
1. Common faults of CNC machine tool servo system
The common faults of CNC machine tool servo system are as follows: ①The servo motor stalls, abnormal noise, temperature rise; ②Servo system alarm; ③The accuracy of positioning is decreased; ④The inertia factor of the servo system is changed; ⑤The axis starts scattered or mis-correction; ⑥Static pressure during positioning is overflow; ⑦The positioning difference is too large, etc.
2. Maintenance and troubleshooting of CNC machine tool servo system
2.1 Maintenance of servo system to ensure the normal running of CNC machine tool
① Observation and inspection should be done regularly to understand the working conditions of the servo system. The most important thing is to check whether the working conditions of the servo motor meet the requirements. The servo system should be inspected at least once a week and the motor oil should be changed once a year.
② Pay attention to the wiring, keep the terminal screw lock, ensure that the power connector and IO connector are correctly connected, ensure that the motor cable and encoder cable are correctly wired, and pay attention to the reasonable placement of cables.
③The transmission part should also be maintained. Generally, the string belt should be checked and adjusted every 75 working hours and the turning belt should be changed every 150 hours.
2.2 Troubleshooting of CNC machine tool servo system
① If the servo motor stalls, first eliminate the mechanical problems of the spindle, bearing, shaft and the mechanical parts that do not move, then check the servo motor wiring, power supply, and current.
② When the servo system alarms, pay attention to the prompt information, identify what the system and module require, and check the relevant parameters for mis-set adjustments.
③The inertia factor of servo system is too large or too small, the user can check the link of the servo system, and make the adjustment of the inertia factor according to the actual situation.
④When the axis starts scattered or mis-correction, check the whole system after powering on, also check the wiring, parameters and other aspects.
⑤During positioning static pressure overflow, pay attention to the adjustment of static pressure after the static pressure alarm starts.
⑥The positioning difference is too large should check whether the mechanical parts are serious wear, deformation and lubrication problem, check the parameters and program of servo system, and adjust the initial value of encoder to make sure that the accuracy of the system positioning is within the specified range.
Conclusion
In a word, the maintenance and troubleshooting of CNC machine tool servo system should be combined with the actual conditions. Find out the root cause of the fault and take corresponding measures to eliminate the fault to make sure that the system can work stably.
