The key to preventive maintenance of CNC machine tools is to strengthen daily maintenance. The main maintenance work includes daily inspection, weekly inspection, monthly inspection, quarterly inspection, and semi-annual inspection. Preventive maintenance of CNC machine tools is as follows:

1. daily inspection of CNC machine tools

The main items include a hydraulic system, spindle lubrication system, guide rail lubrication system, cooling system, and air pressure system. The daily inspection is carried out according to the normal conditions of each system to be tested. For example, when testing the process of the spindle lubrication system, the power indicator should be turned on and the oil pump should operate normally. If the power indicator is not on, the spindle should be kept stopped and contact the mechanical engineer. Repair.

2. weekly inspection of CNC machine tools

The main items include machine parts and a spindle lubrication system, which should be properly inspected every week, especially machine parts, to remove iron filings and external debris.

3. monthly inspection of CNC machine tools

It mainly checks the power supply and air dryer. Under normal conditions, the power supply voltage is 180v-220v and the frequency is 50Hz. If there are exceptions, they should be measured and adjusted. The air dryer shall be disassembled once a month, then cleaned and assembled.

4. quarterly inspection of CNC machine tools

The quarterly inspection shall be mainly conducted from three aspects: machine tool, hydraulic system, and spindle lubrication system. For example, when checking the machine tool bed, it mainly depends on the accuracy of the machine tool and whether the level of the machine tool meets the requirements of the manual. If there is any problem, please contact the mechanical engineer immediately. When checking the hydraulic system and the main shaft lubrication system, if there is any problem, replace it with new lubricating oil and clean it.

5. semi-annual inspection of CNC machine tools

After half a year, check the hydraulic system, spindle lubrication system, and x-axis of the machine tool. If there is a problem, replace it with new oil, and then carry out cleaning work.

After knowing and mastering the knowledge of preventive maintenance, we can better understand and necessarily master the causes and treatment methods of abnormal phenomena in the oil pressure system. For example, when the oil pump does not refuel, abnormal pressure, noise, and other phenomena occur, we should know the main reasons and the corresponding solutions.

The causes and treatment of abnormal phenomena in petroleum pressure system should be understood from three aspects:

• The main reasons for not injecting the oil pump may be low liquid level in the oil tank, reverse rotation of the oil pump, low speed, high oil viscosity, low oil temperature, blocked filter, excessive volume of the oil suction pipe, inlet suction air, shaft and rotor damage, etc. the main reasons have corresponding solutions, such as oil filling, confirmation mark, replacement when reversing the pump, etc.

• Abnormal pressure means that the pressure is too high or too low. The main reasons are improper pressure setting, poor movement of pressure regulating valve coil, abnormal pressure gauge, leakage of oil pressure system, etc. The corresponding solutions include opening and cleaning according to the specified pressure setting, replacing the ordinary pressure gauge, and checking according to each system.

• The noise is mainly generated by the oil pump and valve. When the valve has noise because the flow exceeds the rated standard, the flow shall be adjusted appropriately; When the oil pump has noise, there are various reasons and corresponding solutions, such as high viscosity and low oil temperature of the oil, and the solution increases the oil temperature; When there are bubbles in the oil, release the air in the system.