The correct operation and maintenance of CNC equipment can prevent abnormal wear and tear of the machine tool and avoid sudden failure of the machine tool. Careful maintenance of the machine tool can maintain the long-term stability of the machining accuracy of the machine tool and prolong the service life of the machine tool. This work must be highly valued and executed from the management level of the factory!
▌ Person responsible for maintenance
1. The operator is responsible for the use, maintenance and basic maintenance of the equipment;
2. Equipment maintenance personnel are responsible for equipment maintenance and necessary maintenance;
3. The workshop management personnel are responsible for the supervision of the operators and equipment maintenance of the entire workshop.
▌ Basic requirements for the use of CNC equipment
1. Numerical control equipment requires to avoid places with dampness, excessive dust and corrosive gas;
2. Avoid direct sunlight and other heat radiation, and keep precision numerical control equipment away from equipment with large vibrations, such as punching machines, forging equipment, etc.;
3. The operating temperature of the equipment should be controlled between 15 degrees and 35 degrees. The precision processing temperature should be controlled at about 20 degrees, and temperature fluctuations should be strictly controlled;
4. In order to avoid the influence of large power fluctuations (greater than plus or minus 10%) and possible instantaneous interference signals, the numerical control equipment generally adopts dedicated line power supply (for example, it is divided into one way from the low-voltage power distribution room for the use of numerical control machine tools), and a voltage stabilizing device is added. And so on, can reduce the impact of power supply quality and electrical interference.
▌ Maintenance of daily machining accuracy
1. After starting up, it must be preheated for about 10 minutes before processing; the machine that is not used for a long time should extend the preheating time;
2. Check whether the oil circuit is unblocked;
3. Place the workbench and saddle at the center of the machine before shutting down (move the three-axis stroke to the middle position of each axis);
4. The machine tool is kept dry and clean.
▌ Daily maintenance
1. Daily cleaning of machine tool dust and iron filings: including machine tool control panel, spindle taper hole, tool cart, tool head and taper handle, tool magazine arm and tool magazine, turret; XY axis sheet metal guard, machine tool Internal flexible hose, tank chain device, chip groove, etc.;
2. Check the lubricating oil level to ensure the lubrication of the machine tool;
3. Check whether the coolant in the coolant tank is enough, and if it is not enough to add it in time;
4. Check whether the air pressure is normal;
5. Check whether the air blowing in the cone hole in the spindle is normal, wipe the cone hole in the spindle with a clean cotton cloth, and spray light oil;
6. Clean the tool magazine arms and knives, especially the claws;
7. Check whether all signal lights and abnormal warning lights are normal;
8. Check whether there is leakage in the oil pressure unit tube;
9. Clean and sweep the machine after the daily work is completed;
10. Keep the environment around the machine clean and tidy.
▌ Weekly maintenance
1. Clean the air filter of the heat exchanger, the filter of the cooling pump and the lubricating oil pump;
2. Check whether the tool pull bolt is loose and whether the knife handle is clean;
3. Check whether the origin of the three-axis machine is offset;
4. Check whether the movement of the tool changer arm of the tool magazine or the rotation of the tool head of the tool magazine is smooth;
5. If there is an oil cooler, check the oil-cooled oil, if it is below the scale line, please add oil-cooled oil in time;
6. Clean the impurities and moisture in the compressed gas, check the amount of oil in the oil mist separator, check whether the solenoid valves work normally, check the air tightness in the pneumatic system, because the quality of the pneumatic system directly affects the replacement Knife and lubrication system;
7. Prevent dust and dirt from entering the CNC device. There are generally oil mist, dust and even metal powder in the air in the machine shop. Once they fall on the circuit board or electronic device in the CNC system, it is easy to cause the insulation resistance between the components to decrease, and even cause the components and the circuit board to be damaged. .
▌ Monthly maintenance
1. Detect the lubrication of the shaft track, and the track surface must ensure good lubrication;
2. Check and clean the limit switch and bumper;
3. Check whether the oil in the oil cup of the knife cylinder is enough, and if it is not enough, add it in time;
4. Check whether the indicator plates and warning nameplates on the machine are clear and exist.
▌ Semi-annual maintenance
1. Disassemble the shaft anti-chip guard, clean the shaft oil pipe joint, ball guide screw, three-axis limit switch, and check whether it is normal. Check whether the effect of the hard track scraper on each axis is good;
2. Check whether the servo motor and head of each axis are operating normally, and whether there is any abnormal sound;
3. Replace the oil of the hydraulic unit and the oil of the tool magazine deceleration mechanism;
4. Test the clearance of each shaft, and adjust the compensation amount if necessary;
5. Clean the dust in the electric box (make sure the machine tool is closed);
6. Comprehensively check whether all contacts, connectors, sockets and switches are normal;
7. Check whether all keys are sensitive and normal;
8. Check and adjust the mechanical level;
9. Clean the cutting water tank and replace the cutting fluid.
▌ Annual professional maintenance or repair
Note: Professional maintenance or repairs should be carried out by professional engineers.
1. The grounding protection system should have perfect continuity to ensure personal safety;
2. Regularly check vital parts such as circuit breakers, contactors, single-phase or three-phase arc extinguishers. If the wiring is loose and the noise is too loud, find out the cause and eliminate hidden dangers;
3. Ensure that the cooling fan in the electric cabinet is operating normally, otherwise it may cause damage to the vitality parts;
4. The fuse is blown and the air switch frequently trips. The cause should be found and eliminated in time;
5. Check the vertical accuracy of each axis and adjust the geometric accuracy of the machine tool. Restore or meet the requirements of the machine tool. Because geometric accuracy is the basis of the overall performance of the machine tool. For example, poor XZ and YZ perpendicularity will affect the coaxiality and symmetry of the processed workpiece, and the poor perpendicularity of the spindle to the table will affect the parallelism of the processed workpiece and so on. Therefore, the restoration of geometric accuracy is the focus of our maintenance;
6. Check the wear and clearance of the motors and screw rods of each axis, and check whether the supporting bearings at both ends of each axis are damaged. When the coupling or bearing is damaged, it will increase the noise of the machine tool, affect the transmission accuracy of the machine tool, damage the screw cooling seal ring, cause the leakage of cutting fluid, and seriously affect the life of the screw and spindle;
7. Check the protective cover of each axis and replace it if necessary. If the protective cover is not good, it will directly accelerate the wear of the guide rail. If there is a large deformation, it will not only increase the load of the machine tool, but also cause greater damage to the guide rail;
8. Straightening of the screw rod, because some users may deform the screw rod after the machine has a collision or the gap between the plug and iron is not good, which directly affects the machining accuracy of the machine tool. We first relax the screw rod to make it in a natural state, and then install the screw rod in accordance with the maintenance regulations to ensure that the screw rod is not subject to tangential force as much as possible during the movement, so that the screw rod is also in a natural state during processing;
9. Check and adjust the belt drive system of the machine tool spindle, properly adjust the tightness of the V-belt to prevent the machine from slipping or losing rotation during processing, replace the spindle V-belt if necessary, and check the pressure belt of the 1000r/min spindle high and low gear conversion The amount of oil in the wheel cylinder. Add when necessary. Lack of oil will cause malfunctions during low-grade conversion, which will seriously affect the surface roughness during milling and reduce the cutting torque;
10. Cleaning and adjustment of the tool magazine. Adjust the rotation of the tool magazine to make it parallel to the table, replace the circlip if necessary, adjust the angle of the spindle orientation bridge and the rotation coefficient of the tool magazine, and add lubricating grease to each moving part;
11. Prevent the system from overheating: Check whether the cooling fans on the CNC cabinet are working properly. Check whether the air duct filter is clogged. If too much dust accumulates on the filter and it is not cleaned in time, it will cause the temperature in the CNC cabinet to be too high;
12. Regular maintenance of the input/output device of the numerical control system: check whether the transmission signal line of the machine tool is damaged, whether the interface and connector screws and nuts are loose or falling off, whether the network cable is firmly inserted, and the router is clean and maintained;
13. Regular inspection and replacement of DC motor brushes: Excessive wear of DC motor brushes affects the performance of the motor and even damages the motor. For this reason, the motor brushes should be regularly checked and replaced. CNC lathes, CNC milling machines, machining centers, etc. should be checked once a year;
14. Regularly check and replace the storage battery: Generally, the CMOS RAM storage device in the CNC system is equipped with a rechargeable battery maintenance circuit to ensure that the system can maintain the content of its memory during the period when the system is not powered. Under normal circumstances, even if it has not failed, it should be replaced once a year to ensure that the system works normally. The battery replacement should be carried out under the power supply state of the CNC system to prevent the information in the RAM from being lost during the replacement;
15. Clean the electrical components in the control cabinet, check and tighten the tightening state of the terminal; clean and clean the CNC system control module, circuit board, fan, air filter, heat sink, etc.; clean the internal components of the operation panel, the circuit board, Fan, check the tightness of the connector.
Post time: Oct-22-2021