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Reasons for common failures of CNC bending machine

Views:48     Author:Site Editor     Publish Time: 2020-07-07      Origin:Site Inquire

Cause analysis and elimination of common failures of CNC Press Brake bending machines:


The noise of the oil pump of the CNC Press Brake bending machine is too loud (Warm up too fast), the oil pump is damaged


1. Leakage in the suction line of the oil pump or the liquid level of the oil tank is too low, causing the oil pump to suck.


2. The oil temperature is too low, the viscosity of the oil is too large, resulting in high oil absorption resistance.


3. The oil filter at the suction port is blocked and the oil is dirty.


4. The pump is damaged (injured when the pump is installed) and hit by any knocks.


5. Coupling installation problems, such as axial overtightening, the motor shaft and the oil pump shaft are not concentric.


6. After the pump is installed, the machine will be reversed for a long time or no oil will be added.


7. The outlet high-pressure oil filter is blocked or the flow rate does not reach the standard.


8. The oil pump sucks air (there is oil, but there is air at the oil pump suction port).


9. If it is a plunger pump, the height of the return line may be set too low.


10.The oil temperature is too high, resulting in a decrease in viscosity (within 60°C).


11. The hydraulic oil contains water, which can cause damage to the high-pressure filter.



The system of CNC Press Brake bending machine has no pressure or the pressure cannot be built up


1. Oil pump steering error or oil pump damage.


2. Whether the pressure gauge is damaged.


3. Whether the pressure control valve has electrical signal or the valve is blocked.


4. The pressure plug-in valve is blocked and stuck, and the oil cannot be sealed.


5. The filling valve is stuck (the slider does not slow down).


6. The compensation amplifier is adjusted too small.


7. The pressure can only reach a certain value, use the method of directly supplying 24V to judge whether the valve oil pump has a problem.



The pressure of the bending machine is built slowly


1. The damping hole at the X port of the pressure valve may be blocked.


2. The cartridge valve at the pressure valve may be inflexible.


3. Possible electrical problems: use a direct 24V voltage test for the solenoid pressure valve, or test the spool of the solenoid pressure valve with something.


4. Whether the high-pressure oil filter is blocked.



There is an impact sound when going down


1. Impact sound caused by loose rail plate.


2. The black position of the grating ruler is wrong.


3. The setting value of the delay parameter before fast down is too small.



The slider does not move quickly


1. Is there any electrical signal or stuck in the valve.


2. Whether the electromagnetic proportional directional valve has an electric signal or the spool has no action, it is stuck (check the feedback voltage).


3. The mechanical part is too tightly connected, such as the rail plate is too tight, the cylinder is too tight.


4. The filling valve is closed and cannot be opened so that no oil can be absorbed.


5. Grating ruler problem.


6. Check whether the foot switch is intact.


7. Close the filling valve after the lower valve is energized, no oil can be sucked from the upper chamber.


The pause time of the speed conversion point of the slider is long


1. Air is sucked into the upper chamber of the cylinder, and the pressure build-up time is long (leakage from the self-suction line).


2. The flow rate of the liquid filling valve or the self-priming pipeline is small, or the speed of the slider is too fast to cause vacuum suction.


3. The filling valve is not fully closed and the pressure in the upper chamber decreases slowly.


4. After the lower valve is energized, close the filling valve, and the upper chamber can not absorb oil.


5. Misalignment of the proportional valve leads to different openings and out of sync.


6. Decrease the fast down speed and whether the test stops.


7. The magnitude of the quick down pressure has an effect on the closing of the filling valve, excluding the quick down pressure.


8. Pressure parameter adjustment in the delay phase before working.


9. The damping hole of the control line of the filling valve is too small, forming a pressure difference.


10. CNC system parameters (delay before slow down).


11. CNC system parameters (slower gain parameter decreases).


The slider does not slow down


1. Whether the electromagnetic proportional directional valve has an electric signal or the spool has no action, it is stuck.


2. The system cannot build pressure.


3. The filling valve is stuck, or the sealing ring of the filling valve is leaking.


4. Slow down the valve if there is no electrical signal or stuck.


5. Back pressure is too high or slow down pressure is too low.

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