Application and features of hydraulic press
This hydraulic press is suitable for all types of metal material suppression processes, including punching, bending, flanging and more. Furthermore, it can be used for calibrating, pressing and forming metal products.
The hydraulic press has an independent power supply and electrical system, and uses a button for common control. Its operations are managed by a programmable PLC controller, allowing adjustment and semi-automatic operation.
The working pressure, pressing speed and travel range of this hydraulic press can be customized based on specific technological needs.
Hydraulic press structure overview
This hydraulic press comprises a master motor and control mechanism, integrated through piping and electrical devices.
The main engine includes a machine frame, master cylinder, stroke limiting device and more.
The control mechanism comprises a hydraulic pumping station (power system) and an electrical panel.
The structure and functions of the above-mentioned parts are as follows:
The structure of the hydraulic press
The machine structure mainly comprises a beam, workbench, hydraulic pad, slider, vertical columns and clamping nuts.
The adjusting nut, the four basic columns, the upper beam and the workbench are firmly fixed at both ends of the machine frame by means of fixing nuts, with the slider located at its center.
Accuracy is adjusted using the adjusting nut and lock nut fixed to the beam.
The slider and master cylinder rod are connected by locknuts and feature four columns for up and down movement. Both the slider and the movable bench are equipped with T-channels, which facilitates the installation of the dies.
Master cylinder
The master cylinder is secured to the upper beam via cylinder bosses and large locknuts.
The piston lower end connection has a flange, screw and slider, while the piston heads are made of cast iron and equipped with a reverse seal ring on the outside and an “O” shaped seal ring on the inside to form two oil chambers.
The cylinder opening is also equipped with sealing rings and secured by flanges to ensure the sealing of the lower chambers. Both the upper and lower sides of the flange are also equipped with a sealing ring.
Hydraulic cushion
The hydraulic cushion is installed on the bench and fixed to the upper cylinder using a locking nut, allowing up and down movement. The structure of the upper cylinder is the same as the master cylinder.
Electrical cabinet
The electrical panel can be moved freely and has buttons, time relays and an magnetic detector on its surface.
Stroke limiting device
The stroke limiting device is located on the right side of the machine and comprises a bracket, ram, limit switch and more. The slider can be adjusted by changing the position of the ram.
Hydraulic pump station (power system)
The hydraulic pumping station comprises an oil tank, high pressure pump, motor, cartridge valve and more. The tank is welded and has a filter screen inside.
Hydraulic system theory
The theory of the hydraulic system is shown in the hydraulic theory drawing and the attached list of action sequences. Let's use the semi-automatic work cycle as an example to demonstrate hydraulic theory:
First, connect the power and press SB3 and SB5 to start the engine.
At this point, all electrical valves are still in an inactive state and the oil leaving the high pressure pump will return to the oil tank. The system is in a state of cyclic circulation without load.
With both hands, press SB6 and SB7. At this time, solenoids YA1 and YA5 will turn on and oil from the high pressure pump will flow into the upper chamber of the master pump. YA5 being turned on will cause valve 11 to connect with P and B, A and T. The oil in the lower chamber will flow back to the oil tank through valve 11, and the slider in an unsupported state will move quickly downwards due to its own weight.
At this time, the oil in the pump is incompetent to supplement the upper chamber of the master cylinder and form negative pressure, which will suck the oil infusion valve to open, causing the oil in the oil supply drum to infuse into the upper chamber of the master cylinder. tightly. Therefore, the slider will decrease quickly.
When the slider moves down and approaches switch SQ2, the switch will release signals to continue power YA1 and turn off YA5. Then the oil must overcome the pressure of the support valve before returning to the oil tank, and the lower chamber will form reverse pressure, reducing the descent speed. Therefore, the slider cannot go down depending on its own weight and slows down.
When the slider goes down and touches the work pieces, and the system pressure increases to the prescribed pressure on the SPI gauge, the system will give the signal to unload the solenoid. The pump will enter a no-load circulating state and the time relay KT1 will connect and enter a hold time delay condition.
When the delay increases to the preset time, the KT1 delay contacts release the signal to power YA2 and YA6, and the low pressure valve adjusts the system oil and generates pressure. The system will be in the low pressure state, and the pump oil will open the discharge valve on the infusion valve, discharging the high pressure oil into the upper chamber.
During the time, activate the time relay KT2 and start the timed discharge.
When the preset time of KT2 for pressure relief ends, KT2 outputs the signal to charge YA2 and turn off YA6. Then all the oil from the pump will flow into the lower chamber of the master cylinder to increase the backstroke pressure. Oil from the upper chamber flows back to the brew drum through the master valve of the brew valve to push the slider back.
When the backstroke approaches the prescribed position SQ1, the system will issue signals to discharge YA2 and stop the backstroke. Meanwhile, the YA3 will be charged and the system will flow into the lower chamber of the upper cylinder. Its pressure can be adjusted by the overflow valve and automatically expels the parts until they touch the SQ5.
When pressing the SB13 button, YA4 and YA6 will be loaded and P and A of the valve will be connected. The T and B connection will open valve 20b and enter the upper chamber of the upper cylinder, carrying out the recoil action of the upper cylinder. Charging the YA6 can lower the oil pressure in the lower chamber of the master cylinder, preparing it for the next work cycle.
At this point, a full circulation has been completed.
Electrical System Overview
Brief introduction of hydraulic press
The hydraulic press was designed to operate on a 380V, 50Hz power supply, with control circuit voltage supplied by a 220V transformer.
The press includes a dedicated electrical cabinet that can be placed in a convenient location. The cabinet has a door with switches, control buttons and signal lamps. Inside the cabinet are several controllers, including a power switch, programmable controller, thermal relay, AV contractor, time relay, transformer, intermediate relay, and more.
Depending on the requirements of the pressing technology, the machine can be operated in two ways: manual or semi-automatic. In manual mode, operators adjust the machine and die and perform actions such as slider lowering, backstroke, ejection and piston retreat by pressing the corresponding buttons to start and stop work.
In semi-automatic mode, a single pressing cycle can be started by pressing the “work” button.
Technical parameters for drive device and electrical part
The hydraulic press uses two sets of Y180L-6 three-phase squirrel cage asynchronous motors with a power of 22kW, operating at ~380V and 1470rpm.
The hydraulic system's directional control solenoid valve is driven by 16 wet-type electromagnets operating at 24V DC.
The main technical parameters displayed on the electrical data label are as follows: total power of 44kW, voltage of ~380V, three-phase system, frequency of 50Hz, rated general fuse current of 100A and protection index IP54.
Stroke signaling components
The function of each limit switch is as follows:
SQ1 – Backstroke cursor limit switch: This switch is used to detect the final position of the cursor during the backstroke movement.
SQ2 – Backstroke cursor signal switch: This switch is used to send a signal to the control system when the cursor reaches a specific position during your backstroke movement.
SQ3 – Limiter limit switch: This switch is used to detect the limit position of the limiter during its movement.
SQ4 – Upper limit switch on the hydraulic cushion: This switch is used to detect the upper position of the hydraulic cushion.
SQ5 – Hydraulic cushion lower limit switch: This switch is used to detect the lower position of the hydraulic cushion.
Electrical operation method
Brief introduction to current technological procedures:
First, start the engine, ensuring that the direction of rotation of the engine is consistent with the direction of the pump. Otherwise, the system may not work or even break.
Home position: Use the inching action to move the slider to the extreme position. Then, the limit switch SQ1 starts to work, ejecting the piston to the low position and activating the limit switch SQ5.
Operating procedures:
- Turn the SA1 key to the “semi-automatic” position.
- Adjust limit switches SQ1-SQ10 and SP1-SP2 appropriately according to technical requirements.
- After completing the above-mentioned steps, press the “press with both hands” button. The machine will start operating according to the prescribed processing procedure until the following actions are completed:
- SQ1 signaling, slider descends quickly
- SQ2 signaling, slider descends slowly
- SP1 signaling, slider extends pressure retention time
- KT1 signaling, slider pressure relief
- KT2 signal, backstroke slider
- At this point, a full semi-automatic circulation action has been completed. To implement further actions, the corresponding buttons need to be pressed.
Other actions
Emergency Stop: In case of emergency where the machine needs to stop all work immediately, press the SB1 button. The machine will stop working immediately.
Emergency Stroke: In the event of an emergency where the slider needs to return course immediately, press the SB1 button. The machine will stop working immediately and the slider will return to course.
Power cut: When using the machine, the first step is to turn the rotary switch to the “on” position. When finishing work, turn the rotary switch to the “off” position.
Electrical interlock device and electrical protection
6.1 The master circuit must incorporate an automatic switch for short circuit protection. The motor must be equipped with a thermal overheat relay for overload protection. The control circuit must use a small-sized high-interruptible circuit breaker in case of a short circuit.
6.2 The hydraulic press must be equipped with a photoelectric protection program, and the user can prepare a photoelectric protector with the following interface specifications: 220V power supply, wire nº “0, 12” for power supply and wire nº “60, 84” for signal open retention.
6.3 All electrical equipment must be equipped with special grounding devices for safety purposes.
Hydraulic press electrical components list:
| Code | Name | Model Specification | Amount | Comments |
|---|---|---|---|---|
| M1.2 | Motor | Y180L-6 | two | 22kW |
| M3 | Motor | Y132S-4 | 1 | 5.5 kW |
| QF1 | Small High Interruption Circuit Breaker | DZ47-63 | 1 | 3P30A |
| QF2 | Small High Interruption Circuit Breaker | DZ47-63 | 1 | 2P3A |
| QF3 | Small High Interruption Circuit Breaker | DZ47-63 | 1 | 1P3A |
| QF4.5 | Small High Interruption Circuit Breaker | DZ47-63 | two | 1P1A |
| QF6.7 | Small High Interruption Circuit Breaker | DZ47-63 | two | 1P6A |
| KA1-19 | Intermediate relay | RE-407AL | 19 | 24V |
| CC | ||||
| SQ1-10 | Limit switch | GB0524NA | 10 | |
| SA1 | Button | LAY7-11Y/2 | 1 | |
| SA2.3 | Button | LAY7-20X/2 | two | |
| SB3.5 | Button | LAY7-11D/2 | two | HL2.3 |
| Belt lamp | ||||
| SB2.4 | Button | LAY7-11BN/1 | two | |
| SB6.7 | mushroom head button | LAY7-11/M | two | |
| SB20 | mushroom head button | LAY7-11/M | 1 | |
| KM1-6 | AC Contactor | 3TF46/220V | 6 | |
| KM7 | AC Contractor | 3TB43/220V | 1 | |
| CLP | Programmable Controller | FXON-60MR | 1 | |
| KT1,2 | time relay | JSS20/~220V | two | |
| KT3.4 | time relay | JSZ0/~220V | two | |
| QS | air switch | DZ20-100/34 | 1 | |
| TC | Control transformer | JBK3-400 | 1 | |
| YOU | DC power | 1 | ||
| AA1-19 | Electromagnet | 17 | Follow with hydraulic | |
| HL1 | Signal lamp | LAY7-XD/25 | 1 | ~6V White |
| HL4.5 | Signal lamp | LAY7-XD/21 | two | ~6Vd Red |
Hydraulic press installation and testing
When unloading the hydraulic press at the destination, first carefully wipe off the anti-rust oil. When hanging the machine, pay attention to selecting the center of gravity and place a protective pad at the contact position to avoid using thin plate for loading, which may damage the gauges and components.
The hydraulic press must be installed on a concrete foundation designed according to the attached drawing. The user must design other waterproofing measures and safety lighting devices based on actual conditions.
The installation steps of the hydraulic press are as follows:
- Place the hydraulic pad on the bench and then place the movable bench on top. Insert the columns into the four holes in the slider and bench. Install the power mechanism and electrical panel, making sure everything is level. Finally, use foundation screws to secure the press to the ground.
- Hang and place the master cylinder and top beam on the column during installation. Lock the master cylinder piston to avoid accidents. Screw the nut and remove the fastener.
- Connect the piping, electrical circuit and stroke limit device according to the sketch drawing, hydraulic theory drawing and electrical theory drawing. Fill the clean tank with the appropriate amount of oil, the recommended amount being approximately 1200L.
- Open the pump oil valve and fill the oil completely to eliminate air in the pump. Loosen the pressure adjustment valve handle (safety valve). At this point, almost all of the preparation for testing the machine has been put into place.
- Turn on and start the engine. The direction of rotation must be in accordance with the specification. If not, change the power connectors. Then officially start the engine and let the oil pump run without load.
- Turn the key to the “adjust” position and press the SB8 button to let the master piston descend. The piston head must be properly positioned in the slider hole. Then install the connecting nut between the piston and slider, leaving a gap of 3 to 5 mm on the connecting flange. Adjust the pressure valve to increase the pressure in the master cylinder by up to 5MPa. Tighten the connecting nut with a wrench under pressure-holding conditions.
- Press the SB9 button to allow the slider to move backwards. Place two pressure test plates on the bench, with the center of the plate under the piston rod. The test board must be size f320x650(mm), and the top and bottom must be parallel with a parallelism error of less than 0.02/500mm. The plate must be able to withstand pressure of 500T or more. Adjust the parallelism and verticality between the slider and the bench. Finally, secure the upper beam and fixing nut.
- Test under load conditions. Refer to the hydraulic theory drawing and adjust the back valve pressure until the slider does not slip in any position. Make sure that the pressure is not too large and that the pressure of the upper chamber of the master cylinder is preferably less than 1 MPa when decreasing slowly. The pressure range should be controlled between 5MPa-25MPa, divided into three times from 80t to 500t.
Common faults and troubleshooting solutions
| No. | Faults, breakdowns | Reasons | solutions |
|---|---|---|---|
| 1 | Action failure | 1. The electrical connection wire is loose or incorrectly connected | 1. Inspect the electrical part |
| 2. Control oil tank pressure is insufficient | 2. Properly increase oil pressure up to 1.5 MPa | ||
| 3. Oil volume too small | 3. Add more oil | ||
| two | Sliding tracking | 1. Some air build up in the system or pump sucks in air | 1. Inspect if any air enters the oil tube, then move the timings and increase the pressure |
| 2. Improper precision adjustment or lack of oil in the vertical column | 2. Add some oil to the vertical column, readjusting the accuracy | ||
| 3 | The slider maintains some pressure as it slowly descends | Too high bearing pressure | Adjusting the rear valve to fully release the pressure in the upper chamber, max. the pressure must be less than 1 MPa |
| 4 | The slider slides strongly when stopping the machine | 1. Sealing ring at the cylinder mouth leak | 1. Inspect the cylinder rim, if it leaks, replace it |
| 2. The pressure is too small or there is a leak | 2. Adjust pressure and check cylinder edge | ||
| 5 | The pressure gauge needle swings strongly | 1. There is some air in the pressure gauge oil tube | 1. Slightly loosen the connector to release air when increasing pressure |
| 2. Mechanical vibration of the pipeline | 2. Firmly secure the tubing | ||
| 3. The pressure gauge is broken | 3. Change the pressure gauge | ||
| 6 | High pressure stroke speed is not enough, increase pressure slowly | 1. High pressure flow is too small | 1. Adjust according to the pump instructions and the eccentric can adjust to 5 steps when 25MPa |
| 2. Pump wears out or burns out | 2. If the rear oil port is badly damaged, disassemble to inspect | ||
| 3. Leak between systems heavily | 3. First, inspect whether the infusion valve has been closed, and then inspect other components respectively | ||
| 7 | Pressure relief is very fast under the condition of pressure retention | 1. The mouth of the valve in question is not completely sealed or there is a leak in the piping | 1. Inspect the infusion valve and the condition of pressure retention and relief |
| 2. The sealing rings are damaged | 2. Replace new sealing rings |
The faults mentioned above are just common faults and are for reference only. When encountering real faults during daily use, it is necessary to analyze the possible causes and then solve the problems one by one.
Maintenance and safety operation rules
Proper use of the hydraulic press and compliance with maintenance and safe operation rules are essential to extend the life of the machine and ensure safe production.
Therefore, it is important to be familiar with the structural performance and operating procedures of the machine. In addition, we provide some maintenance and safe operation tips based on general conditions for user reference.
Hydraulic press maintenance
We recommend adopting N46 hydraulic oil. If using machine oil or turbine oil, selection should be based on temperature. When the ambient temperature is below 20°C, 20# machine oil or 22# turbine oil are acceptable. When the ambient temperature is above 30°C, 30# or 40# machine oil is acceptable. The oil temperature should be controlled between 15°C~60°C.
The oil must be rigorously filtered before being infused into the oil tank.
The working oil must be changed every year and the first change interval must not exceed three months.
Regularly infuse lubricating oil into the slider. The exposed surfaces of the column and piston must be kept clean and infused with machine oil each time before work.
The acceptable eccentricity is 75mm under a nominal concentrated load pressure of 500t.
Inspect and calibrate the pressure gauge every six months.
If the hydraulic press is stopped for a long time, all machined surfaces must be cleaned and coated with anti-rust oil.
Hydraulic Press Safety Operation Rules
Operators who are not familiar with the structural properties or operating procedures of the hydraulic press may not start the machine without permission.
All die overhaul and adjustment work must not be carried out while the machine is running.
If there is any serious leakage or abnormal situation such as unreliable action, excessive noise or vibration, etc., the machine should be stopped and the reasons should be analyzed. Faulty machines cannot be put into use.
It is prohibited to exceed the maximum eccentricity distance and maximum load.
It is prohibited to exceed the maximum stroke and the closed height of the die must not be less than 500 mm.
The electrical grounding device must be reliable and safe.
List of Vulnerable Hydraulic Press Components
Vulnerable components of the master engine, master cylinder and upper cylinder.
| Part name | Drawing number and code | Component name | Material | Amount | Comments |
|---|---|---|---|---|---|
| Master Engine | Guide sleeve | HT200 | 8 | Attached drawings | |
| Master cylinder | TDM-YA320 | Sealing ring | PU | 3 | |
| TDM-YA295 | Sealing ring | PU | 1 | ||
| D320x5.7 | “O” shaped ring | Oil resistant rubber | two | GB1235-76 | |
| D220x5.7 | “O” shaped ring | Oil resistant rubber | two | GB1235-76 | |
| piston head | HT200 | 1 | Attached drawings | ||
| Cylinder edge guide sleeve | HT200 | 1 | Attached drawings | ||
| Cylinder | D140x3.1 | “O” shaped ring | Oil resistant rubber | 2×4 | GB1235-76 |
| D70x3.1 | “O” shaped ring | Oil resistant rubber | 2×4 | GB1235-76 | |
| TDM-YA100 | Sealing ring | PU | 2×4 | ||
| TDM-YA140 | Sealing ring | PU | 3×4 | ||
| cylinder guide sleeve | HT200 | 1×4 | Attached drawing | ||
| piston head | HT200 | 1×4 | Attached drawing |
Hydraulic Press Diagram
Fig 1. Top view of the hydraulic press work table
Fig 2. Top view of the hydraulic press ram
Fig 3. Hydraulic Press Master Cylinder
Fig 4. Hydraulic press master cylinder assembly diagram
Fig 5. Drawing of the hydraulic press ejection cylinder assembly
Fig 6. Hydraulic Principle Diagram of Hydraulic Press
Fig 7. Electrical Drawings of the Hydraulic Press
Fig 8. Electrical box hydraulic press wiring diagram
Fig 9. Hydraulic Press Lubrication Diagram
Fig 10. Hydraulic Press Guide Bushing
Fig 11. Hydraulic press guide ring
Fig 12. Hydraulic Press Foundation Drawing
