How To Maintain CNC Drilling and Milling Machines?
I. Daily maintenance: basic cleaning and inspection
1. Equipment cleaning
Body surface: wipe the body with a soft cloth after daily operation to remove aluminum chips, oil stains and dust to avoid accumulation affecting equipment operation.
Work surface: use a brush to clean the aluminum chips on the work surface to prevent the chips from getting stuck on the guide rail or lead screw; if there is oil stain, wipe it with a neutral detergent.
Cooling system: check the coolant tank, remove the aluminum chips deposited at the bottom, and replace the coolant regularly (it is recommended to replace it every 2-3 months).
2. Lubrication system inspection
Manual lubrication points: manually add lubricating oil before daily operation according to the positions marked in the equipment manual (such as guide rails, lead screws) (lithium-based grease or guide rail oil is recommended).
Automatic lubrication pump: check the oil level in the oil tank to ensure sufficient oil; observe whether there is any abnormal sound or abnormal indicator light when the lubrication pump is working. If the pump oil is not smooth, it needs to be repaired in time.
3. Electrical system inspection
Check whether the buttons and indicator lights on the control panel are in normal use, whether the connectors of the wires are loose or aged, and replace them in time if there are safety hazards.
Clean the dust in the electrical cabinet regularly, maintain good ventilation, and prevent poor heat dissipation from causing overheating of components.
II. Regular maintenance: deep maintenance (performed periodically)
1. Weekly maintenance
Spindle maintenance:
Check the spindle connection. If there is abnormal noise or jamming during rotation, the bearing needs to be adjusted or replaced.
Wipe the spindle taper with a clean cloth and apply anti-rust oil to prevent oxidation from affecting the tool installation accuracy.
Transmission system:
Check the belt tightness (the belt droop when the thumb presses should be ≤10mm). Too loose will cause transmission slippage, and too tight will accelerate belt wear.
If there is oil leakage in the gearbox, replace the seal in time and add gear oil (API GL-4 grade gear oil is recommended).
2. Monthly maintenance
Guide rails and lead screws:
Remove the guide rail guard, remove the aluminum chips and oil accumulated inside, clean the guide rail surface with kerosene, and apply lubricating oil after drying.
Check the clearance of the screw nut pair. If the axial movement exceeds 0.05mm, adjust the preload or replace the screw.
Tool magazine and tool change mechanism:
Clean the tool magazine tool sleeve, check whether the tool positioning pin is loose, and whether the robot moves smoothly when changing tools to avoid tool jams.
3. Quarterly / semi-annual maintenance
Precision calibration:
Use a dial indicator to check the flatness of the work surface (the error should be ≤0.03mm/1000mm). If the error is out of tolerance, re-grind or adjust the pad.
Calibrate the verticality of the spindle (place a square on the work surface, and the dial indicator reading deviation is ≤0.02mm/300mm when the spindle rotates).
Hydraulic system:
Replace the hydraulic oil (it is recommended to use 46# anti-wear hydraulic oil), clean the oil tank and filter, and prevent impurities from clogging the oil circuit.
III. Special maintenance of key components
1. Spindle system
Cooling and heat dissipation: Check whether the spindle cooling system is normal. The water temperature of the water tank should not exceed 35℃. If the cooling effect is poor, clean the pipes or replace the water pump in time.
Bearing life: It is recommended to replace the spindle bearing after 5000 hours of cumulative operation. Special tools should be used when replacing to avoid knocking and damaging the bearing.
2. CNC system
Battery replacement: The CNC system memory battery (usually a lithium battery) needs to be checked once a year. When the voltage is lower than 3.6V, it should be replaced in time to prevent program loss.
Parameter backup: Back up the CNC system parameters regularly (every quarter). If the system fails, backup and restore can be done in advance to reduce downtime.
3. Protective device
Check whether the machine tool protective cover and chip conveyor are intact. If the chip conveyor chain plate is broken or deformed, please replace it in time to avoid aluminum chips accumulating and damaging the equipment.
IV. Fault prevention and safety precautions
1.Common troubleshooting
Fault phenomenon | Possible causes | Workaround |
Spindle speed is unstable | Inverter failure or belt slippage | Repair the inverter and adjust the belt tension |
Drilling position offset | The guide rail is worn or the screw clearance is too large | Replace the guide rail slider and adjust the screw preload |
Coolant not coming out | The water pump is clogged or the pipe is broken | Clean the water pump and replace damaged pipes |
2. Key points for safe operation
Be sure to cut off the power before maintenance and erect a "under maintenance" warning sign to avoid accidental start-up.
When disassembling parts, mark the positions of each part to prevent errors during installation.
Please wear protective gloves during maintenance operations to avoid injuries.
V. Maintenance records and plans
Establish equipment maintenance records to record the time, content, replaced parts and fault handling of each maintenance, so as to facilitate tracing and predicting maintenance cycles.
Develop maintenance plans based on production loads. For example, the lubrication cycle can be shortened when running at high loads (such as adding 1 lubrication per week).
