From vibration to loss of precision: A quick guide to 7 types of faults in electro-hydraulic servo bending machines

Fault 1: Abnormal vibration when the slider moves downward

Possible causes: servo valve contamination causing valve core jamming, insufficient guide rail lubrication, insufficient accumulator nitrogen pressure

Solution:

Replace hydraulic oil and clean servo valve (oil cleanliness must comply with ISO 4406 ≤18/16/13 standards)

Replenish guide rail lubricant

Check accumulator pressure (should be 70% of system working pressure)

Fault 2: Bending angle repeatability accuracy exceeds tolerance

Key inspection points:

Grating ruler repeatability positioning accuracy (needs ≤±0.01mm)

Lower die V-mouth fillet radius (must be replaced if it exceeds R0.3mm)

Hydraulic system pressure holding capacity (pressure drop <5% in 10 minutes) Compensation measures: Enable the angle real-time compensation function in the CNC system

Fault 3: Servo motor overload alarm

Troubleshooting steps:

Check the mechanical transmission resistance (whether the guide rail/mold is stuck)

Measure the oil pump outlet pressure (normal value ≤21MPa)

Check the balance of the three-phase current of the motor (deviation>10% requires repair of the driver)

Fault 4: Indentation or scratch on the workpiece surface

Solution:

Use acetone to thoroughly clean the mold working surface

Reduce the processing pressure of copper/aluminum by 30%

Replace the polyurethane protective film every 8 hours

Set the downward speed to ≤1mm/s when processing precision parts

Fault 5: The hydraulic system temperature is too high

Cooling measures:

Check the cooling water flow (need>20L/min)

Replace high viscosity index hydraulic oil (HVLP46)

Optimize work Parameters to reduce no-load speed

Fault 6: "Following error exceeds limit" of CNC system

Solution:

Adjust the tension of synchronous belt (use professional tension meter to check)

Reset PID parameters (focus on adjusting proportional gain Kp)

Add magnetic ring to encoder line (especially near inverter)

Fault 7: Slider slides down after emergency stop

Hazardous fault handling:

Main valve leakage test (no pressure and pressure maintenance for 15 minutes, slide down > 2mm, need to replace valve)

Disassemble and inspect the sealing surface of hydraulic lock (focus on checking pilot hydraulic control check valve)

Daily maintenance points of electro-hydraulic servo CNC hydraulic sheet metal bending machine

Daily: Check oil level and clean grating ruler

Weekly: Test the repeat positioning accuracy of each axis

Quarterly: Replace filter element (filtration accuracy β ≥ 200)

Yearly: Comprehensively inspect the sealing of hydraulic pipeline