Press Brake Hydraulic System Operation

Press brake is one of the most commonly applied bend machines. It is now more efficient with hydraulic system. This machine has a significant place in the process of plate metal treatment. It determines the final quality, effective processing as well as accuracy. Press brakes consist of frame, slide blocks, hydraulic framework, head load racks, rear gauge, molds, electric mechanism and so on. (See fig. 1) 

Fig. 1

Perpendicular downwards pressure emerges as a result of parallel operating hydraulic barrels to bring dies upon bend beam to accomplish the bend procedure. Hydraulic mechanism is responsible for simultaneous bend procedure and the location of hydraulic cylinders at the full load of the machine.

Now, let us reveal more on brake hydraulic framework operation.

Hydraulic Mechanism

A common bend procedure of the top bend beam implies: 

1. Starting oil pomp

Motor rotates in the course of the pomp pointer, clockwise rotation, running the axle piston pomp. Oil pours via pipelines into the piston plates and electromagnetic piston to come back to the tank. If No. 19 piston is shut, oil in the bottom hollow of No. 20 cylinder stays fixed.

2. Downwards Motion

Rapidly dropping movement of press brake is generated by bend beams, self-heft of accessory as well as oil pressure. While processing hydraulic cylinders have not got any shaft hollow through filling valves, so, the shaft hollow produces back pressure and oil returns rapidly.

The rapid ahead moving rises at the upper dead core. In a short while sliders slow down at a particular space from bend plate. If No. YV1, 24YV6, 13YV4 and 17YV5 electromagnet valves operate, slide block descends quickly. Dropping velocity gets set up through No. 18. No. 20 cylinder down cavity oil pours into tank by the means of No.19, 18 and 17. No.20 top cavity oil gets discharged via No. 21. At the time of slide falling on limiting switch No. 9 YV1, 8 YV2, 11 YV3, 13 YV4, 24 YV6 electromagnetic valves operate making rams convert into operational velocity. If sliders are not synchronized, No. 15 mechanically gets fixed. Slide block dropping location is limited via mechanic blocks in cylinders.

3. Bending

This step starts when non-rod chamber pressure is built up. Bend velocity gets restricted via the provided oil amount. For one thing, proportional piston direction adjusts it. Meanwhile, directional valve synchronizes the bend beam operations and the location of down dead core. Bend strength is restricted via proportional piston limiting pomp pressures. Velocity value, sync, location as well as pressure are determined through CNC.

Pedal switches manage electromagnetic operation duration. It includes No.9 YV1, 8 YV2, 11 YV3, 13 YV4 and 24 YV6 that make joggling space at the time slide blocks fall. Sliding descend velocity gets controlled via No. 16. Sliders are adjusted through No. 11 YV3 and 24. YV6. The same electromagnetic operation duration realizes movement space of sliders.

4. Pressure Release

The no-rod chamber pressure begins to release as soon as it comes to the dead core base or in a short while. Thus, metal gets enough time for formation and later improvement of size accuracy of pieces. Pressure retention as well as release become possible because of vertical direction valve due to CNC. To boost treatment effectiveness, retraction period must not be long. To escape the unloading effect in the framework, extending discharging period is necessary. In a word, stress release curving must be fluent, not tough. The efficiency of processing is produced by vertical valves.

5. Return of master cylinder

Pomp flow and hydraulic cylinders bear rod chamber stress space that defines the utmost returning velocity. Most commonly near the quickest velocity. Returning speed demands simultaneous functioning from stress retraction of rod chamber to the top dead core.

At the time of returning No.8 YV2 electromagnetic pressure needs resetting. Next No.11 YV3, No. 24 YV6 electromagnetic begin working, sliding block and returning velocity remain permanent. 

6. Press Brake Pressure Setting

No.6 large pressure flow, No. 11 electromagnetic valves mostly maintain the press brake indicated power. No. 14 flow valves regulate returning strength to avoid damaging the equipment because of overloading. Working pressure is possible to see in No. 7 gauge. No. 10 accumulator nitrogen stress mostly regulates the pressure necessary for No. 19, 21 valves operation.