CNC Hydraulic Press Brake for steel plate

Steel Press Brake as a common industrial machinery equipment has wide applications. Therefore, the analysis of hydraulic system fault treatment in bending machine has practical significance. Sheet metal press brakes systems are very complex, so the failure is difficult to troubleshoot.

Shearchy steel press brake hydraulic system structure

The main hardware structure includes machine frame, working table and clamping plate. The main function of electro-hydraulic system is to start the oil pump. Then, motor drives oil pump to provide driving force. The hydraulic system includes main oil pump, hydraulic system, hydraulic cylinder, press cylinder, hydraulic pipeline, etc.

Fault analysis of hydraulic bending machine system

  • Speed control loop

A common fault is the speed control loop fault.

Common speed regulation methods of hydraulic system: throttle speed regulation, volume speed regulation and throttle volume combined speed regulation.

We should make sure that the rate remains constant as the load on the device changes. And try to ensure the reliability of the speed control loop, improve the efficiency of the equipment and reduce the system heat. The following are the main failure types of speed control loop.

The speed of hydraulic system cannot be kept constant

As the load on the device changes, so does the rate.

There may be several reasons:

  1. Electrical circuit problem

When designing the electrical system, the manufacturer did not take changes of load into account. Engineers did not design the corresponding speed regulation mechanism, resulting in the cylinder speed changes.

  1. Pressure difference between before and after of flow control valves

The pressure difference between before and after of flow control valve should be within the range of 0.2-0.3mpa. In this range, users can ensure the stability of the flow when adjusting the flow area. If it is less than this range, it may lead to flow instability, which will lead to rate instability.

The movement speed of bending machinery is not up to standard

  1. High oil temperature leads to a decrease in the rate.
  2. Increased load leads to decreased speed.
  3. The actuator must not move at low speed.
  • Directional control loop

  1. The drop of cylinder cannot be controlled accurately.
  2. The cylinder drops automatically.
  3. The plunger cylinder drops intermittently.
  4. The plunger cylinder drops intermittently.
  5. In addition, there are solenoid valve itself problems or serious pollution caused by the valve core stuck and other problems.
  • Hydraulic control system

Control system failure may cause the cylinder sliding block tension standards and return speed is not enough.

The main reasons include:

  1. Hydraulic cylinder seal is not enough, resulting in leakage.
  2. Insufficient pressure of relief valve.
  3. Hydraulic pressure is insufficient due to excessive internal leakage
  4. The wear of the spool of reversing valve makes it difficult to move.
  • Synchronization of the system

From the piston cylinder itself analysis:

The piston leakage, that is, between the piston and the cylinder appeared a large gap. And left and right piston cylinder leakage is not equal. As a result, the speed of the synchronous axis is not the same.

Analysis from oil pipeline:

When the steel press brake falls fast, the back pressure of the lower chamber is different due to the unequal movement resistance on the oil line. As a result, the reflux flow of the two cylinders is different, which leads to different rates. This is the reason for the asynchrony.

CNC Press Brake Hydraulic System Troubleshooting Measures

We can obviously see from the above fault analysis, in order to effectively solve the hydraulic steel bending press system fault, first of all, to have a deep understanding of the hydraulic system mechanism. Understand the hardware structure and working characteristics of the bending press. Different types of bending machines have different systems, but they work in much the same way. After understanding the working mechanism, it is necessary to observe and test specific faults, so as to properly troubleshoot and deal with them.

  • For the hydraulic cylinder:

On the one hand, we need to reduce the internal leakage phenomenon, reduce the difference between the two cylinder leakages. On the other hand to ensure that the hydraulic bending machine in the design to be as reasonable as possible, taking into account the different external load, close to the actual situation of the work.

  • For the oil pipeline:

We also should ensure the balance of the two pipelines, determine the balance center and reduce the friction on the surface, thereby reducing the resistance.

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