18 CNC bending machine common faults and processing methods

1. Excessive noise vibration of oil pump (too fast heating) and damage of oil pump

1. Air leakage of oil pump suction pipe or low liquid level of oil tank causes empty oil pump

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

3. The oil filter at the oil inlet is blocked and the oil is dirty

4. Pump damage (pump injury during installation) caused by rough operation

5. Coupling installation problems, such as axial too tight, motor shaft and oil pump shaft are different centers

6. After installation, the pump is tested for a long time reversal or no refueling  CNC bending machine 

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

8. Empty suction of oil pump (there is oil, but there is air at the suction port of oil pump)

9. If it is a piston pump, it may be that the height of the oil return port pipeline is set too low

10. If it is Hoebiger, the oil pump may need to deflate  steel bending machine price

11. Oil temperature is too high, resulting in reduced viscosity (within 60°C)

12. The hydraulic oil contains water, which will cause the blockage and damage of the high-pressure filter element

Two, the system has no pressure or pressure can not be built up

1. Oil pump steering error or oil pump damage

2. Pressure gauge is damaged

3. Pressure control valve has no electrical signal or valve blockage

4. Pressure cartridge valve is blocked, stuck, and can not seal the oil

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

6. The compensation amplifier is too small.

7. The pressure can only reach a certain value, and the method of directly giving 24V is used to determine whether there is a problem with the valve oil pump

Three, the pressure is built slowly (REXROTH hydraulic system)

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

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

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

4. Whether the high pressure oil filter is blocked

Four, fast under the impact of sound

1. Impact sound caused by loosening of guide plate

2, the grating ruler black piece is not in the right position

3, fast down before the delay parameter setting value is too small

Five, there is no quick action of the slider

1. Quick down valve has no electrical signal or stuck

2. Solenoid proportional directional valve has no electrical signal or spool has no action, stuck (check the feedback voltage)

3. The mechanical part is too tight, such as the guide plate is too tight, the oil cylinder is too tight

4. The filling valve is closed and can not be opened, so that the oil can not be absorbed

5. Grating scale problem

6. Check the connection if the foot switch is in good condition

7. After the slow down valve is powered, close the liquid filling valve, and the upper chamber can not absorb oil

Six, the slider speed conversion point pause time is long

1. The upper chamber of the cylinder inhales air, and the pressure builds up for a long time (air leakage from the suction pipe)

2. The flow of the filling valve or the suction pipe is small, or the speed of the sliding block is too fast, resulting in vacuum absorption

3. The filling valve is not completely closed, and the pressure of the upper chamber decreases slowly.

4. After the slow down valve is powered, close the liquid filling valve, and the upper chamber can not absorb oil

5. Proportional valve in the middle is not the same as the opening, go out of sync

6. Reduce the speed of the fast down test is there any pause

7. The size of the fast downpressure has an effect on the closing of the filling valve, so eliminate the fast downpressure

8. Pressure parameter adjustment in the delay stage before work

9. The damping hole of the control line of the liquid filling valve is too small, resulting in pressure difference

10. Numerical control system parameters (slow down before delay)

11. Numerical control system parameters (gain parameter decreases at slow speed)

Seven. No slow down action of the slider

1. Solenoid proportional directional valve has no electrical signal or spool has no action, stuck

2. The system cannot build pressure

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

4. Whether the slow down valve is electric signal or stuck

5. Too high back pressure or too low downpressure

Eight, the slider slow down the movement of vibration, swing, noise

1. The cylinder discharge pressure oil contains bubbles

2. The friction of slider guide rail is too large, and there is no lubricating oil

3. The gap between the guide plate and the connecting surface is large, or the upper and lower are uneven

4. The level of rack and worktable is not adjusted properly

5. Balance valve is blocked

6. Check whether the quick down valve is energized and opened

7. The numerical control system parameters (gain), or the setting of labor speed is too large

8. The back pressure valve is loose, and the resistance on both sides is different

9. Solenoid proportional valve coil has no bias, proportional valve median signal is correct

10. Whether the signal of proportional servo valve is disturbed, the inspection method is the same as above

11. The cylinder sealing ring holds the piston rod dead, and the resistance is large (change the PTFE hard sealing ring test)

12. The spherical washer on the grating ruler is not installed, the slide seat does not move smoothly, and there is something wrong with the grating ruler's communication line

13. The pressure curve is wrong. There is not enough pressure during labor

14. A small amount of leakage occurs in the pressure seal O-ring of the filling valve

Nine, slow down when the synchronization deviation is large

1. Synchronous fault detection system (grating scale)

2. Proportional directional reversing valve

3. Leakage of quick down valve

4. Large difference in back pressure on both sides

5. Oil temperature is too low

6. Oil in the upper and lower cavities of the oil cylinder

7. Numerical control system parameters

Ten, the slider at the bottom of the dead point of pressure oscillation, jitter

1. There may be a problem with the raster ruler

2. The cylinder discharge pressure oil contains bubbles

3. Balance valve is blocked

4. Numerical control system parameters (gain)

5. Back pressure valve problem, resistance on both sides is not the same

6. Solenoid proportional valve problem: the median may be wrong

7. Loose lifting bolt of the cylinder → shake at the lower dead point, wrong height, inaccurate bending Angle, and sound when bending

11. No return movement or slow return movement of the slider

1. Whether the electromagnetic proportional directional valve is reversing or not, and whether it is damaged

2. Whether the system has the build pressure or the return pressure is too small

3. One side of the filling valve may be stuck or not fully open

4. When the slow down valve is powered up, close the liquid filling valve, and it cannot be returned quickly

5 numerical control system: programming Angle is too small, can not reach the bending programming dead point

6. Zero control system parameters

7. Damage of grating ruler or wiring problem

8. Check whether the system pressure is set up slowly

XII. Shake and shake when the slider returns

1. Too high or too low return pressure

2. System parameters or PLC and DM02 modules

3. Proportional valve coil has no deflection

13. Slider slide (upper dead point)

1. Adjustment of back pressure valve

2. Leakage of back pressure valve or quick down valve

3. Oil in the upper and lower cavities of the oil cylinder

4 proportional valve bias

5. The support stability of the sealing ring is not enough, and the slider slides after deformation

6. Determine the reason for the slide - after removing the proportional valve, observe whether the oil outlet of the lower chamber is producing oil

Fourteenth, the bending Angle error is large

1. Check whether the compensation deflection of the compensation cylinder is large and can not be completely restored to zero

2, check whether the fast clip wedges are loose

3. Check whether there is any change in the dead point under each bend

4. Check whether the installation of the bow pull is standard and whether the screw hole is jacked

5, the plate itself change (thickness, material, stress)

6, the grating ruler is not loose

7, positioning accuracy is not allowed: proportional valve zero offset value is appropriate, positioning can not reach the bottom dead point so that can not return

Large error of straightness of bending

1, check the compensation cylinder compensation deflection is appropriate

2, check whether the fast clip wedges are loose

3. Check whether the horizontal and vertical mold fitting surface on the slider is deformed

4. Check whether the upper and lower molds are out of shape

5, the plate itself change (thickness, material, stress)

6. Check whether the table (neutral board) is out of shape

Leakage of hydraulic pipe or collapse of oil pipe

2. Check whether the tubing installation meets the requirements (extension length, pipe diameter, wall thickness, sleeve, too tight, too loose nut, bending radius, etc.)

3. Whether there is impact and vibration on the oil pipe

4. Check whether the pipeline is collided with other interference

5. The pipeline is not fixed with pipe clamp

17. Matters needing attention during installation and maintenance of hydraulic system:

1. The valves of the paint seal shall not be dismantled or adjusted by themselves

2. The valve works normally after cleaning. The oil must be replaced immediately and the oil tank must be cleaned

3. The oil pump shall not be knocked or impacted during installation, and the oil pump shall be refueled in advance before trial

4, the valve installation can only carry its body, shall not contact any solenoid valve

Analysis of common faults of rear stopper

1, the rear stopper can not move :① check whether the drive alarm

② Check the limit switch of each axis

Check the reliability of the connector

2. Drive alarm

3, X, R axis operation is not stable, there is jitter

4, positioning accuracy change: (1) mechanical problems (whether loose, impact)

② Electrical → unidirectional positioning

③ Parameter adjustment

(4) whether the tensioning wheel is loose, whether the screw connecting screw is loose

2, overload alarm: whether the ball screw can rotate easily, the steel ball may be damaged