Analysis of CNC bending machine usage failure

Synchronized CNC Press Brake

Too loud oil pump noise (too fast heating process), and damaged oil pump

1. The oil pump suction line leaked air or the oil tank liquid level was too low, caused the oil pump to suck air.

2. The oil temperature was too low and the oil viscosity was too large, resulted high oil absorption resistance.

3. The suction port’s oil filter was clogged and the hydraulic oil was dirty.

4. The pump was damaged (the motor reversed for a long time or not enough hydraulic oil inside)

5. Coupling installation problems, such as excessive axial tightening, the motor shaft and the oil pump shaft center were not leveling.

6. The oil temperature was too high, caused the viscosity to decrease (within 60°C).

7. Water contained in the hydraulic oil, which caused blockage and damage to the high-pressure filter element.

No pressure in the system or non pressure going up

1. The reversal of the motor caused damage to the oil pump.

2. Whether the pressure gauge is damaged.

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

4. The pressure cartridge valve was blocked, stuck, and could not seal the oil.

5. The filling valve was stuck (the slider did not slow down).

6. The pressure could only reach a certain value, directly power on 24V to determine whether there is a problem with the oil pump.

Slow pressure rise (Rexroth)

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

2. The cartridge valve at the pressure valve may not move flexibly.

3. Possible electrical problems: directly test the solenoid valve 24V voltage, or use something to test the solenoid valve pressure valve spool.

4. Is the high-pressure oil filter blocked?

Impact sounds during fast down

1. Impact sounds caused by loose rail plates.

2. The position of the grating ruler was wrong.

3. The setting value of the fast down delay parameters was too small.

The slider did not move quickly down.

1. Is there any electrical signals or the quick-down valve stuck?

2. Whether the electromagnetic proportional directional valve has an electric signal or the spool is moving or stucking (check the feedback voltage).

3. The mechanical part connected too tightly, for example, the guide rail plate was too tight.

4. The filling valve closed and could not be opened, so no oil can be sucked in it.

5. The problem of grating ruler.

6. Whether the foot switch is in good condition, and check whether the wiring is loosen.

7. After energized the slow down valve, close the filling valve and the upper cavity cannot suck oil then.

Long pause time of slider speed conversion point

1. The upper cavity of the oil cylinder sucked air, and the pressure built up for a long time already (the self-priming pipeline leaked).

2. The flow rate of the filling valve or self-priming pipeline was small, or the sliding speed was too fast, resulted in vacuum suction.
   

3. The filling valve was not completely closed, and the pressure in the upper cavity slowed down.

4. After energized the slow down valve, close the filling valve, and the upper cavity could not suck oil then.

5. The wrong position of the proportional valve led to different openings and out of sync.

6. Decrease the fast down speed, and check whether there would be any pauses in the test.

7. The size of the fast down pressure had an effect on the closing of the filling valve, eliminated the fast down pressure.