English Author: Site Editor Publish Time: 2026-03-11 Origin: Site
Ⅰ.Daily maintenance: Building a solid defense line for the stable operation of equipment
1.Comprehensive inspection before startup
Environmental and appearance inspection: Confirm that the working environment temperature of the machine tool is between 10℃ and 30℃, and the humidity does not exceed 70%. Avoid factors such as dust, oil stains, and electromagnetic interference from affecting the operation of the equipment. Clean the chips and dust on the surface of the machine tool, and check whether the protective door, operation panel and other components are in good condition to prevent debris from entering the precision parts such as the guide rail and lead screw.
Inspection of the lubrication and cooling system: Check the liquid levels in the lubricating oil tank and cutting fluid tank. If they are insufficient, add the corresponding grade of oil and cutting fluid in time to ensure that the pipelines of each lubrication point and the cooling system are unobstructed. For machining centers that use pneumatic tool changing, it is necessary to open the air pump to drain water or check the working status of the dryer to prevent the control valve from rusting due to a damp air source.
Initial inspection of the electrical system: Check whether the cooling fan of the electrical cabinet is operating normally and whether the cabinet door is well sealed to prevent dust from entering and causing a short circuit. Before powering on, check if there is any condensation inside the electrical cabinet. In a high-temperature and high-humidity environment, power on for preheating first. Wait until the condensation disappears before starting the equipment
2.Real-time monitoring during operation
Status observation: During operation, closely monitor changes in the machine tool's sound, vibration, temperature, etc. If abnormal sounds, excessive vibration or local temperature rise occur, stop the machine immediately for inspection. For instance, if the main shaft makes an irregular and shrill sound during operation, it might be a signal of bearing wear or insufficient lubrication.
Parameter and Alarm Monitoring: Pay attention to the parameter and alarm information on the display screen of the numerical control system. If alarms such as servo overload and positioning deviation occur, adjust the processing parameters or check the corresponding components in a timely manner according to the prompts. At the same time, regularly check the no-load current of each axis servo drive system to ensure it is within the normal range.
Inspection of key components: For frequently moving parts such as the tool magazine, tool-changing manipulator, and worktable, observe whether their movements are smooth, and check for any jamming or inaccurate positioning. Check whether the pressure plate bolts of the tooling fixture and the tool holder pull nails are tightened to prevent loosening during the processing.
3.Standardized maintenance after shutdown
Cleaning and Repositioning: After work is completed, thoroughly clean the chips inside the machine tool, especially on the guide rails, lead screws, tool magazines and other parts, to prevent chip accumulation and affect accuracy. Move the worktable to the middle position, return the spindle to its original position, and turn off the auxiliary systems such as the cutting fluid and air source.
Lubrication and Protection: Manually lubricate moving parts such as guide rails and lead screws to ensure they remain in good lubrication during downtime. After turning off the power supply of the machine tool, take proper protective measures for the equipment, such as covering it with a dust cover to prevent dust and moisture from entering.
Data Backup and Record-keeping: Every week, the parameters of the numerical control system and the processing programs are backed up and stored in an independent medium to prevent data loss. Record in detail the equipment operation status, maintenance content and abnormal conditions of the day, form a maintenance history, and provide a basis for subsequent fault investigation.
Ⅱ. Fault diagnosis and elimination: Accurately solve operational problems of equipment
1. Common types of faults and causes
Mechanical faults: The main shaft components are prone to abnormal noises, excessive vibrations, and inability to clamp the cutting tools, which are mostly caused by reasons such as bearing wear, insufficient lubrication, and loose belts. The faults of the feed system are manifested as the workbench jamming and the positioning accuracy exceeding the tolerance. Common causes include the wear of the ball screw, the scratches on the guide rail, and the loosening of the coupling. Faults in the tool magazine and tool changing, such as tool changing jamming and tool dropping, are often related to loose transmission chains, worn mechanical grippers, and insufficient air pressure.
Electrical faults: Servo system faults can cause the motor not to rotate or overload alarms, which may be due to incorrect driver parameters, damaged encoders, or poor cable contact. Sensor failure is manifested as malfunction of the limit switch and abnormal reading of the grating ruler, which is mostly caused by dust coverage, loose wiring and aging of components. Electrical component damage, such as the erosion of contactor contacts and the blowing of fuses, is often associated with voltage fluctuations, current overload, and a humid environment.
Numerical control system failure: Program-related failures include program failure to run and dimensional deviations during processing. The causes include program syntax errors, incorrect coordinate system Settings, and incorrect input of tool compensation parameters. Parameter-based faults are manifested as abnormal machine tool operation and system alarms, mostly due to incorrect parameter modification or loss of parameters caused by a dead battery. System hardware failures such as black screens and malfunctioning keys may be due to a damaged motherboard or aging of the keyboard membrane switches.
Hydraulic and pneumatic faults: Hydraulic systems are prone to insufficient pressure and oil leakage, which are mostly caused by wear of hydraulic pumps, malfunction of relief valves, and aging of oil pipes. Pneumatic system failures such as insufficient air pressure and slow operation are commonly caused by clogged filters, air pipe leakage, and solenoid valve malfunctions.
2. Fault diagnosis methods
Visual inspection method: Preliminarily determine the faulty part through methods such as observing, listening, touching and smelling. Observe the system alarm information, whether the appearance of components is damaged, listen to whether the operating sound of the equipment is abnormal, feel whether the temperature of the motor, bearings and other parts is too high, and smell whether there is a burnt smell inside the electrical cabinet.
Instrument testing method: Use multimeters, oscilloscopes and other instruments to test whether the voltage, current and signal of the electrical circuit are normal. Use measuring tools such as dial indicators and micrometers to check whether the accuracy and clearance of mechanical components meet the requirements.
Isolation and troubleshooting method: By disconnecting non-critical loads and replacing suspected faulty components, etc., gradually narrow down the scope of the fault. For example, when a servo motor is suspected to be faulty, a motor of the same specification can be replaced for testing.
Data analysis method: By combining the machine tool manual, system diagnosis manual, maintenance history and other materials, compare the fault phenomena to find possible causes and solutions.
3. Typical troubleshooting examples
The temperature of the main shaft bearing is too high: If the preload is too large, the preload of the bearing needs to be readjusted. If the bearing is damaged, a new one should be replaced in time. If the lubricating oil is dirty, the spindle box needs to be cleaned and the lubricating oil replaced.
After the tool is clamped, it cannot be released: The pressure of the tool release hydraulic cylinder and the position of the travel switch can be adjusted, or the nut on the disc spring can be adjusted to reduce the spring clamping amount.
If the motor rotates but the tool magazine does not, it is necessary to check whether the coupling and bearing between the motor and the tool magazine are damaged, or whether there is any foreign object blocking the tool magazine. If neither the motor nor the tool magazine rotates, it is necessary to check whether the self-locking circuit, the PLC output signal, and the strong current circuit are faulty.
Ⅲ. Long-term maintenance strategy: Extend the life cycle of equipment
1. Regular precision inspection and adjustment: Every quarter or half a year, the positioning accuracy, repeat positioning accuracy, backlash, etc. of the machine tool are inspected, and precise data is obtained using professional equipment such as laser interferometers and ballbar gauges. If the test results exceed the allowable range, accuracy compensation should be carried out by adjusting the clearance of the lead screw nut pair, replacing worn parts, modifying system parameters, etc.
2. Preventive replacement of key components: According to the equipment user manual and maintenance experience, replace vulnerable parts regularly. For instance, inspect and replace the brushes of the DC motor annually to prevent excessive wear from affecting the motor's performance. Replace the battery used for storage in the numerical control system every 1 to 2 years to ensure that parameters are not lost. Regularly replace the hydraulic oil, cutting fluid, air filter element, etc., to ensure the system is clean and its performance is stable.
3. In-depth maintenance of the electrical system: Check monthly whether the connection terminals of the electrical cabinet are tightened, test whether the grounding resistance meets the requirements, and replace aged cables and insulating materials in a timely manner. Clean the heat dissipation and ventilation system of the electrical cabinet every six months and replace the air duct filters to prevent dust accumulation from causing the system to overheat. For spare printed circuit boards, they should be regularly installed in the system and powered on for operation to prevent damage from long-term idleness.
4. Special Maintenance during the idle period of equipment: When CNC machine tools are not in use for a long time, they should be powered on for a trial run once every 1 to 3 weeks, with each idle run lasting about 1 hour. This is to utilize the heat generated by the machine itself to reduce the humidity inside the machine and prevent electronic components from getting damp. At the same time, regularly check the battery power of the system. If a battery alarm occurs, replace it in time to avoid parameter loss.
