How to maintain CNC machines ?

- Dec 16, 2019-

The key to preventive maintenance of CNC machine tools is to strengthen daily maintenance. 

The main maintenance tasks are as follows: daily inspection, weekly inspection, monthly inspection, quarterly inspection, and semi-annual inspection.

The preventive maintenance of CNC machine tools is as follows:


1. Daily inspection of CNC machine tools


Its main projects include hydraulic systems, spindle lubrication systems, rail lubrication systems, cooling systems, and pneumatic systems. Daily inspection is based on the normal conditions of each system. For example, when testing the spindle lubrication system, the power lamp should be on, and the hydraulic pump should be running normally. If the power lamp is off, keep the spindle stopped and contact the mechanical engineer. Make repairs.


2. Weekly inspection of CNC machine tools


Its main items include machine tool parts and spindle lubrication systems, which should be properly inspected weekly, especially for machine tool parts to remove iron filings and clean up external debris.


3. Monthly inspection of CNC machine tools


Mainly check the power supply and air dryer. The power supply voltage is rated at 180V-220V and frequency 50Hz under normal conditions. If there is any abnormality, measure and adjust it. The air dryer should be disassembled once a month, and then cleaned and assembled.


4. Quarterly inspection of CNC machine tools


The quarterly inspection should be mainly performed from three aspects of the machine bed, hydraulic system, and spindle lubrication system. For example, when inspecting the machine tool bed, it mainly depends on whether the accuracy of the machine tool and the level of the machine tool meet the requirements in the manual. If there is a problem, you should contact the mechanical engineer immediately. When inspecting the hydraulic system and the spindle lubrication system, if there is a problem, the new oil 6oL and 20L should be replaced and cleaned.


5. Semi-annual inspection of CNC machine tools


After half a year, the hydraulic system, spindle lubrication system and X-axis of the machine tool should be inspected. 

If something goes wrong, it should be replaced with new oil and then cleaned. 

After comprehensively familiarizing and mastering the knowledge of preventive maintenance, it is necessary to have a deeper understanding and necessary grasp of the causes and treatment of abnormal phenomena in the oil pressure system. 

For example, when the fuel pump does not inject fuel, the pressure is abnormal, and noise occurs, you should know what the main reasons are and what the corresponding solutions are.


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


(1) The main reasons for non-injection of the oil pump may be low liquid level in the fuel tank, reverse rotation of the pump, too low speed, too high oil viscosity, low oil temperature, clogged filters, excessive suction pipe piping volume, and suction at the oil inlet. The air, shaft, and rotor are damaged. 

There are corresponding solutions to the main reasons, such as filling the oil, confirming the label, and changing it when the oil pump is reversed.


(2) The pressure is abnormal, that is, the pressure is too high or too low. The main reasons are also various, such as improper pressure setting, poor operation of pressure regulating valve coils, abnormal pressure gauges, and leaks in the hydraulic system. 

The corresponding solutions include dismantling and cleaning according to the prescribed pressure settings, changing a normal pressure gauge, and checking each system in turn.


(3) Noise Noise is mainly caused by oil pumps and valves. 

When the valve is noisy, the reason is that the flow rate exceeds the rated standard, and the flow rate should be adjusted appropriately; when the oil pump is noisy, the reason and the corresponding solutions are also various, 

such as high oil viscosity and low oil temperature. To raise the oil temperature; when there are air bubbles in the oil, the air in the system should be vented, etc.


For more details, welcome to check our website: www.lemo-machining.com 

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