Lathe has the characteristics of machine, electricity and hydraulic integration, technology-intensive and knowledge-intensive. It is a kind of advanced processing equipment with high degree of automation, complex structure and expensive. In order to give full play to its benefits and reduce the occurrence of failures, routine maintenance must be done. Therefore, the maintenance personnel of CNC lathes must not only have knowledge of machinery, processing technology, and hydraulics and pneumatics, but also have electronic computers, automatic control, drive and measurement. Technology and other knowledge, so that we can fully understand and master the CNC lathe, and do a good job of maintenance in time.
1. For the main daily maintenance and maintenance of cnc machine tools, first select the appropriate use environment: the use environment of CNC lathes (such as temperature, humidity, vibration, power supply voltage, frequency and interference, etc.) will affect the normal operation of the machine tool, so When installing the machine tool, it should be strictly required to comply with the installation conditions and requirements specified in the machine tool manual. If economic conditions permit, the CNC lathe should be installed separately from ordinary machining equipment for easy repair and maintenance.
2. Numerical control lathes should be equipped with specialized personnel for numerical control system programming, operation and maintenance: these personnel should be familiar with the mechanical parts of the machine tool used, numerical control systems, strong electrical equipment, hydraulic pressure, air pressure and other parts, use environment, processing conditions, etc., and be able to Use the CNC lathe correctly according to the requirements of the machine tool and system manual.
3. Maintenance and maintenance of CNC lathes that are not used for a long time: When the CNC lathe is not in use, the CNC system should be energized frequently, and the CNC lathe should be run dry when the machine is locked. In the mildewy season when the air humidity is relatively high, the electricity should be turned on every day, and the heat of the electrical components themselves should be used to drive away the moisture in the CNC cabinet to ensure the stable and reliable performance of the electronic components.
4. Maintenance and maintenance of the hardware control part of the numerical control system: Let an experienced maintenance electrician check it once a year. Check whether the relevant reference voltage is within the specified range, such as the output voltage of the power module, the reference voltage of the numerical control unit, etc., if it is abnormal, the dust needs to be removed; check whether the electrical components in the system are loosely connected; check that each functional module is running with a fan Check whether the connection between the servo amplifier and the external regenerative discharge unit used by the spindle amplifier is reliable, and remove the dust; check whether the voltage of the memory backup battery used by each functional module is normal, and generally should be replaced regularly according to the manufacturer’s requirements. For machine tools that are out of service for a long time, they should be turned on and run for 4 hours a month, which can extend the service life of cnc machine tools.
5. Maintenance and maintenance of the mechanical part of the machine tool: After the processing of each shift, the operator should clean up the chips scattered on the carriage, guide rail, etc.; pay attention to check whether the chip conveyor is normal during work to avoid accumulation of chips and damage to the guide rail Accuracy endangers the life of the ball screw and the guide rail; before the end of the work, the servo axes should be returned to the origin and then stopped.
6. Maintenance and maintenance of the spindle motor of the machine tool: The maintenance electrician should check the servo motor and the spindle motor once a year. Focus on checking the operating noise and temperature rise. If the noise is too large, find out the cause, whether it is a mechanical problem such as a bearing or a parameter setting problem of the matching amplifier, and take corresponding measures to solve it. For DC motors, the brushes, commutators, etc. should be inspected, adjusted, repaired or replaced to make them work in good condition. Check whether the cooling fan at the end of the motor runs normally and clean the dust; check whether the connecting plugs of the motor are loose.
7. Maintenance and maintenance of the feed servo motor of the machine tool: For the servo motor of the CNC lathe, maintenance should be carried out once in 10 to 12 months, and the machine tool with frequent acceleration or deceleration changes should be maintained once in 2 months.
The main contents of maintenance are:
Use dry compressed air to blow off the dust of the electric brush, and check the wear of the electric brush. If you need to replace it, you need to select the same specifications of the electric brush. After the replacement, run it without load for a certain period of time to make it consistent with the surface of the commutator; check and clean The armature commutator is to prevent short circuit; if there is a speed motor and pulse encoder, it should be inspected and cleaned.
The DC servo motor in the CNC lathe should be inspected at least once a year. Generally, the inspection should be performed when the CNC system is powered off and the motor is completely cooled; remove the rubber brush cap and use a screwdriver to unscrew the brush cover Take out the brush; measure the length of the brush. For example, when the brush of the FANUC DC servo motor is worn from 10mm to less than 5mm, the brush of the same model must be replaced; carefully check the arc contact surface of the brush for deep grooves and cracks, and Whether there are any traces of spark on the brush spring.
If there is the above phenomenon, it is necessary to consider whether the working conditions of the motor are too bad or whether there is a problem with the motor itself. Use compressed air that does not contain metal powder and moisture into the brush hole where the brush is installed, and blow off the brush powder sticking to the wall of the brush hole. If it is difficult to blow clean, use the tip of a screwdriver to gently clean it until the hole wall is completely clean, but be careful not to touch the surface of the commutator. The brush must be newly installed and the brush cover must be tightened. If a new brush is replaced, the motor should be run dry for a period of time to make the brush surface and the commutator surface match.
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