Common Faults of Bending Machines and Troubleshooting Methods

number

Fault

Possible causes of the fault

Method of exclusion

1

The oil pump does not deliver oil or the oil supply is insufficient

Oil pump reverse

Change to clockwise rotation direction

Coupling loose

Re-secure the coupling

Oil level too low

Refuel to at least 80% of the tank capacity

Oil pump does not start

Check the electrical parts

Oil pump damage

Replace the oil pump

The oil suction pipe or oil suction filter is clogged

Clean the filter

2

Insufficient system pressure

Insufficient oil supply

Same as item 1

The throttling hole is blocked and the overflow valve is faulty.

Check, clean or repair the relief valve

The reversing valve is stuck in the middle position

Check, clean or repair the reversing valve

The solenoid coil of the reversing valve is damaged

Replace the solenoid coil

The pressure gauge and switch are damaged, and the displayed pressure is incorrect.

Check or replace the pressure gauge and switch

3

Abnormal noise and vibration in the hydraulic part

The oil suction pipeline is leaking and white foam appears on the liquid surface

Check the pipeline to ensure tightness

The oil suction resistance is too large, the oil suction filter is clogged, the oil viscosity is too high or too low

Clean or replace the oil filter, replace the hydraulic oil with the appropriate viscosity

The hydraulic pump input shaft is not coaxial with the motor shaft

Check and readjust

4

Oil Leakage

The cylinder seal, the O-ring between the valve plate and the valve are damaged or aged.

Replace seals

Loose pipe joints

Tighten the joint or replace

Hose connection is loose

Tighten the joint or replace

There are foreign objects on the sealing surface.

Tighten the screws after removing foreign matter

5

Oil temperature is too high

Insufficient oil in the tank

Add hydraulic oil

The oil viscosity is too high

Adjust hydraulic oil type

System pressurization time is too long

Adjust the pressurization time

The pressure control valve is too high

Reduce the pressure

Oil pump bearing damage

Replace bearings

Large internal leakage of valve group

Check, repair or replace valve

6

Slider crawl

Air enters the hydraulic system

Run at no load for a while to exhaust the air

The cylinder and guide sleeve are not coaxial

Replacement of guide sleeve

The clearance between the slider and the guide rail is too small, the lubrication is poor and the movement resistance increases

Adjust the guide rail clearance and add lubricating oil

The cylinder is seriously damaged

Disassemble the cylinder for inspection and repair

Relief valve stuck

Check and clean the overflow valve

Excessive leakage inside the oil cylinder

Check the cylinder seal and replace it

The center of the cylinder and the guide rail are not parallel

Adjust the parallelism of mechanical parts

7

Different bending angles

The slider is not consistent with the left and right free heights

Adjust the height of the torsion shaft connection part on the rear side of the slider to ensure that the slider is free and at the same height on both sides.

The left and right heights are inconsistent when pressurizing

Adjust the fine-tuning screws on the left and right cylinders, and connect the synchronous shaft after the left and right cylinders are completely consistent.

The connection between the piston rod and the slider is loose

Tighten the loose bolts to eliminate the gap

The mold fixture adjustment pad is loose

After adjusting the upper die to be parallel, tighten the clamp screws

Loose or damaged bearing

Check and remove the bearing for replacement