What is Hydraulic Press Machine
Fig.1 Hydraulic Press Machine Diagram
Hydraulic Press Definition
The hydraulic press is a kind of machine which uses the liquid as a working medium to transfer energy based on PASCAL’s principle to realize various technique.
Generally, the hydraulic press machine consists of three parts: the machine (mainframe), the power system and the hydraulic control system.
Brief Introduction of Hydraulic Press
Hydraulic press machine (also known as hydraulic oil press) is a machine that makes use of the static pressure of the liquid to process metal, plastic, rubber, wood, powder products.
It is often used in pressing and pressing forming processes, such as forging press, stamping, cold extrusion, straightening, bending, flanging, sheet drawing, powder metallurgy, pressing, etc.
Fig.2 Hydraulic Press Machine Structure
Biggest Hydraulic Press
Fig.3 80,000 Ton Die Forging Press
The 80,000-ton die-forging hydraulic press is 27 meters high on the ground and 15 meters underground, with a total height of 42 meters and a total weight of 22,000 tons, which make it the most powerful and strongest hydraulic press in the world
The giant die-forging hydraulic press is a national treasure class strategic equipment which symbolizes the strength of the heavy industry. There are only a few countries in the world that can make such a hydraulic forging press.
Currently, only China, the United States, Russia and France have more than 40,000 tons of die forging presses in the world.
The United States built two of the world’s largest 45,000 ton die-forging presses around 1955, which are still in use today.
In 2001, another 40,000-ton die-forging press was built at the Shultz steel mill in California.
The Soviet Union built two huge 75, 000-ton die-forging presses around 1961.
France bought a 65,000 ton die-forging press from the Soviet Union in 1976 and developed a 40,000 ton die-forging press in 2005 in cooperation with Germany.
China’s first 30, 000-ton die-forging press stalled for nearly 40 years after it was built in 1973.
Until the last two years, several huge presses were developed explosively.
There were 30,000 tons, 40,000 tons and 80,000 tons of die forging presses built in 2012 alone. The 80,000-ton hydraulic press broke the world record held by the former Soviet Union for 51 years.
Die forging press is mainly used to manufacture high strength titanium/aluminum alloy forgings in aerospace, nuclear power, petrochemical and other fields.
In the world, any country with a huge die-forging press is a powerful aviation industry.
Hydraulic Press History
In 1795, the British j. brammer used PASCAL’s principle to create a water press for packaging and pressing vegetable oils.
By the middle of the 19th century, Britain began to use hydraulic presses for forging. The hydraulic press gradually replaced the super-large steam hammer.
By the end of the 19th century, the United States had built 126,00T free-forging hydraulic presses.
Since then, the world has produced more than 20 sets of 10,000T free-forging hydraulic machines, including two made in China (see Fig.4).
Fig.4 Free-forging hydraulic machines
With the development and improvement of the electric high-pressure pump, the forging hydraulic press is developing towards a small tonnage.
After the 1950s, small rapid forging hydraulic press appeared, which could do the things equivalent to the work done by 3-5Ton forging hammer.
In the 1940s, Germany made a huge die-forging press of 18,000T. Since then, the world has produced 18 sets of 18,000T forging hydraulic machines, of which one made in China is 30,000T.
Types of Hydraulic Press Machine
According to the structural form, the hydraulic press machine is mainly divided into:
- Four-column hydraulic press
- Single column hydraulic press (C type)
- Horizontal hydraulic press
- Vertical frame hydraulic press
- Universal hydraulic press
If classified by tonnage, the hydraulic press can be divided into:
- 63T hydraulic press machine
- 100T hydraulic press machine
- 150T hydraulic press machine
- 200T hydraulic press machine
- 250T hydraulic press machine
- 300T hydraulic press machine
- 315T hydraulic press machine
- 500T hydraulic press machine
- 630T hydraulic press machine
- 800T hydraulic press machine
According to the applications, it is mainly divided into metal forming, bending, stretching, punching, powder (metal, non-metal) forming, pressing, extrusion and so on.
Hot forging hydraulic press
As one of the most widely used equipment in the forging industry, the large hydraulic forging machine is able to complete all kinds of free forging technique.
At present, there are series of forging hydraulic presses with 800T, 1600T, 2000T, 2500T, 3150T, 4000T and 5000T specifications.
Four-column hydraulic press
The four pillar hydraulic press is suitable for pressing the plastic material, like powder products forming, plastic products forming, cold (hot) extrusion metal forming, sheet drawing, transverse pressing, bending, penetration, and correction processes.
The four-column hydraulic press can be divided into the four-column two-beam hydraulic press, four-column three-beam hydraulic press and four-column four-beam hydraulic press.
C-frame hydraulic press
Extendable working range, able to lengthen hydraulic cylinder stroke (optional) using three-sided space with max retractability 260mm-800mm. Able to preset working pressure and with heat abstractor device.
Horizontal hydraulic press
The machine parts can be assembled, disassembled, straightened, compressed, stretched, bent, punched, etc to realize one machine with multi-purpose.
The working table of this machine can move up and down, the size expands the opening and closing height of the machine, making it more convenient to use.
Two-pillar hydraulic press
This series of products are suitable for pressing, bending and shaping of all kinds of parts, stamping indentation, flanging, punching and light stretching of small parts. And it also suitable for metal powder products forming.
Adopt electric control, with job motion and semi-automatic cycle, can protect the time of pressure delay, and have good sliding block direction, easy operation, easy maintenance, economic durability.
According to the needs of users can add thermal instruments, ejector cylinder, travel display, counting functions.
It is made based on PASCAL’s law and makes use of fluid pressure transmission.
The two-pillar hydraulic press not only has many types but also has a variety of applications.
If classified by the type of liquid that transferring pressure, the two-pillar hydraulic press can be divided into oil press and water press.
The total pressure produced by water is large and is often used for forging and stamping.
The forging press is also divided into two types: die forging water press and free forging water press.
The die forging water press need to use the mold, while the free forging water press does not.
Working Principle of Hydraulic Press Machine
Fig.5 Hydraulic press mechanism
The area of the large and small plunger is S2 and S1 respectively, and the force on the plunger is F2 and F1 respectively.
According to PASCAL’s principle, the pressure of the confined liquid is equal everywhere, that is, F2/S2=F1/S1=p; F2=F1(S2/S1).
The gain effect of hydraulic pressure is the same as that of mechanical gain. The force is increased, but the work is not gained. Therefore, the motion distance of large plunger is S1/S2 times of that of the small plunger.
The basic principle is:
The oil pump transfers the hydraulic oil to the integrated cartridge valve blocks, and assigned to the upper chamber or lower chamber of the cylinder through the one-way valve and relief valve. Under the action of high pressure oil, the oil cylinder starts to move up and down.
The hydraulic press is a device that makes use of liquid to transfer pressure. The law of PASCAL is applied to the transfer of pressure in a closed container.
The hydraulic drive system of four-column hydraulic press consists of power mechanism, control mechanism, executive mechanism, auxiliary mechanism and working medium.
Usually, the oil pump is used as the power mechanism. One or more pumps are selected to meet the requirement of running speed of the actuator.
- Gear pump for low pressure (oil pressure less than 2.5mp);
- Blade pump for medium pressure (oil pressure less than 6.3mp);
- Plunger pump for high pressure (oil pressure less than 32.0MP).
The function of working medium used in a hydraulic press is not only to transfer pressure but also to ensure the working parts of the hydraulic press machine are sensitive, reliable, long life and less leakage.
The basic requirements of hydraulic press for working medium are:
① Suitable fluidity and low compressibility are available to improve transmission efficiency.
③ Good lubrication performance;
④ Easy to seal;
⑤ Stable performance, long-term work without deterioration.
The hydraulic press uses water as the working medium at first and then uses emulsified liquid by adding a small amount of emulsified oil into the water to increase the lubrication and reduce corrosion.
The oil press with mineral oil as a working medium appeared in the late 19th century. The oil has good lubricity, anti-corrosive and moderate viscosity, which is beneficial to improve the performance of the hydraulic press.
In the second half of the 20th century, a new type of water-based emulsifying solution was developed, which was characterized as “oil inclusion water” rather than “water inclusion oil”.
The outlook of the ” water inclusion oil ” is oil, its lubricity and corrosion resistance are close to oil. Besides, it contains little oil and is not easy to burn. However, water-based emulsions are more expensive, which limiting its spreading.
Hydraulic Press Machine Structure
Fig.6 Hydraulic press machine drive system
The driving system of hydraulic press mainly consists of two types: pump direct drive and pump-accumulator drive.
Pump direct drive
The pump of this drive system provides high pressure working liquid to the hydraulic cylinder. The distribution valve is used to change the direction of the supply liquid. The overflow valve is used to adjust the limited pressure of the system and also acts as a safe overflow.
This drive system has less process, simple structure, the pressure can automatically increase and decrease according to the work required force, which reduced the power consumption. However, the capacity of the pump and drive motor must be determined by the biggest workforce and maximum working speed of the hydraulic press.
This type of drive system is mainly used for medium and small-sized hydraulic press, and also can be used for large (such as 12000T) free forging hydraulic press directly driven by the pump.
There is one or a set of accumulators in this drive system. When the high pressure working fluid supplied by the pump has a surplus, it is stored by the accumulator. When the supply is insufficient to meet the need, it is supplied by the accumulator.
The capacity of the pump and motor can be selected according to the average amount of high pressure working fluid if adopting this system. However, the energy consumption is large, and the system has many processes, the structure is complex due to the constant working fluid pressure.
This kind of drive system is used for large hydraulic press, or a set of the drive system to drive several hydraulic presses.
According to the direction of the force, there are vertical and horizontal hydraulic presses.
Most hydraulic presses are vertical, while the hydraulic presses used for extrusion are horizontal.
According to the structure type, the hydraulic press has two columns, four columns, eight columns, welding frame and multi-layer steel strip winding frame types. Medium and small vertical hydraulic press has the C-frame type.
The c-frame hydraulic press is open on three sides, easy to operate, but less rigid.
The welding frame hydraulic press used for stamping is rigid, open to the front and back, but closed to the left and right.
In the vertical transmission four-column free forging hydraulic press, the oil cylinder fixed on the upper beam, the plunger is rigidly attached to the movable beam. The movable beam is guided by the vertical column and moves up and down under the pressure of working fluid.
There are workbenches on the beam that move back and forth. The upper anvil and the lower anvil are respectively installed under the movable beam and on the worktable.
The working force is borne by a frame consisting of upper and lower beams and columns.
The large and medium-sized free-forging hydraulic press is driven by pump-accumulator usually adopts three working cylinders to obtain three-level working forces.
Outside the working cylinder, there are also balancing cylinder and return cylinder which applies upward force.
Advantages of Hydraulic Press
Compared with the traditional stamping process, the hydroforming process has obvious technical and economic advantages over reduce weight, reduce the number of parts and mold quantity, improve the rigidity and strength, reduce the production cost etc. More and more applications have been made in the industrial field, especially in the automobile industry.
In the automotive industry, aviation, aerospace fields, it is a long-term goal to reduce the structural quality and save the energy in operation. It is also one of the trends of the development of advanced manufacturing technology.
Hydroforming is an advanced manufacturing technology for realizing lightweight structure.
Compared with stamping and welding technology, hydraulic forming technology has the following main advantages:
1. Reduce weight and save materials
For typical parts such as automobile engine bracket and radiator bracket, hydraulic forming parts are 20% ~ 40% lighter than stamping parts. For hollow step shaft parts, the weight can be reduced by 40% ~ 50%.
2. Reduce the number of parts and molds and lower the cost of molds
Hydraulic forming parts usually only need one set of molds, while most stamping parts need more sets of molds. Hydraulic forming engine bracket parts reduced from 6 to 1, radiator bracket parts reduced from 17 to 10.
3. Reduce the welding of subsequent machining and assembly
Take the radiator support, for example, the heat dissipation area increased by 43%, the soldering point decreased from 174 to 20, the process decreased from 13 to 6, and the productivity increased by 66%.
4. Improve strength and rigidity, especially fatigue strength
For example, the rigidity of the hydroformed radiator bracket can be increased by 39% in the vertical direction and 50% in the horizontal direction.
5. Lower production cost
According to the statistical analysis of the used hydraulic forming parts, the average production cost of hydraulic forming parts is 15% ~ 20% lower than that of stamping parts, and the mold cost is 20% ~ 30% lower.
Application of Hydraulic Press
Hydraulic presses can be used for the process of drawing forming, turning, bending and stamping of metal sheet parts. It can also be used in general pressing technology by adding blanking buffer, blanking, moving table devices according to the user needs.
In addition to forging and forming, the three-beam four-column hydraulic press can also be used to correct, press mounting, packing, briquetting and plate pressing.
Suitable materials for the hydraulic forming process include carbon steel, stainless steel, aluminum alloy, copper alloy and nickel alloy.
In principle, all materials suitable for cold forming are suitable for the hydraulic forming process.
It is widely used in automobile parts factory, electronics factory, electric appliance factory, heat treatment plant, automobile parts factory, gear factory, air conditioning parts factory
Besides, hydraulic forming technology has been widely used in automobile, aviation, aerospace and pipeline industries. It is mainly applicable to:
- Hollow structural parts with circular, rectangular or special-shaped sections changing along the axis of the components, such as the special-shaped pipe parts of the exhaust system of an automobile;
- Non-circular hollow frame, such as engine bracket, instrument panel bracket and body frame (accounting for 11% ~ 15% of vehicle quality);
- Hollow shaft parts and complex pipe fittings etc.
Accessories for Hydraulic Press Machine
|1||The gear pump|
|2||Hydraulic overflow valve|
|10||Hole use YX ring|
|11||Combined seal ring|
|12||The gear pump|
How to Build A Hydraulic Press Machine
DIY 5 ton hydraulic press
Hydraulic Press Machine Operation
Different types of hydraulic press machine are operating differently. And every hydraulic press machine manufacturer will provide the operation manual together with the hydraulic press when delivered. The manual will be the best training materials for you to learn various key points about how to use the hydraulic press.
If you use four pillar hydraulic press machine, you can also take our user manual of hydraulic press for reference:
Hydraulic Press Machine Commissioning
- Turn the working mode switch to the “inching move” position and loosen the adjusting handle of the pressure control valves on the power station.
- Switch on the power and jog the motor to check if the rotation is consistent with the specified rotation. After the completion of the work, the motor can be officially started, so that the oil pump can operate at an empty load for no less than 5 minutes. Then, check whether all parts are normal. If there is no abnormal phenomenon, the system pressure can be raised to around 6Mpa to prepare for the next work.
- Press the “press” button to make the piston of the main cylinder descend. The piston head is required to touch the upper plane of the slider. Then install the large flange and ensure the distance between the flange end face and the upper plane of the slider is 5mm. When the pressure rises to a pre-set 6Mpa and stop, tighten the connecting bolt with a wrench in a pressure-holding state.
- Press the “return” button to raise the slider to the upper dead center and place the test anvil (metal pad) in the center of the worktable. The height of testing anvil should not be less than 500mm, the length and width should not be less than 600mm, the parallelism of upper and lower surfaces of testing anvil should be less than 0.02/500mm, and the sufficient strength to bear full load should be provided.
- Adjust according to the accuracy standard specified in the certificate of conformity. Generally, the parallelism between the lower plane of the slider and the working table is adjusted first. The specific method is to adjust the four adjusting nuts under the upper beam after adding the pressure. After passing, tighten the four lock nuts above.
- When the pilot valve “F2” is adjusted to stop at any position of the slider in the test running as described above, there shall be no sliding. However, it should be noted that the pressure value should ensure the need for the return force. When descending slowly, the pilot valve “F3” shall be adjusted to the upper cavity of the main cylinder, and the pressure value shall be less than 1Mpa.
- The pressure range is generally 5MPa ~ 25Mpa, i.e. 60T ~ 315T. When the electric contact pressure gauge “F12” is adjusted, the pilot valve “F1” shall also be adjusted accordingly. Generally, the system pressure should be about 1Mpa higher than the predetermined pressure of the contact pressure gauge “F12”. When is used when the pressure less than 5Mpa, table “F12” may have upthrust.
- When drawing, the adjustment of pressure side force is pilot valve “F7”, which should be fixed at 25Mpa. The adjustment of system pressure is pilot valve “F1”, which is usually fixed at 25Mpa.
- To measure the speed of each action stroke according to the requirements, and whether the movement of each unit of the travel limiter is reliable.
- After the measurement of pressure protection performance, stop the vehicle under pressure, and the pressure drop of 10 minutes is required to be no more than 2Mpa.
- Measure machine accuracy again
At this point, the whole commissioning of hydraulic press machine is finished and can be put into production.
Hydraulic Press Machine Maintenance
- The recommended oil for hydraulic press machine is to be #32 and #46 anti-wear hydraulic oil, with oil temperature ranging from 15 to 60 ℃.
- The oil should be strictly filtered before it is allowed add into the tank.
- The working oil should be replaced once a year, and the first time replacement should not exceed three months.
- The sliding block shall be lubricated frequently, and the appearance of the vertical column shall be kept clean frequently. The machine oil shall be injected before each work.
- Under the nominal pressure of 500T, the maximum allowable eccentricity of the central load is 40mm. Excessive eccentricity can easily lead to post tension or other adverse phenomena.
- Calibration and inspection of pressure gauges every six months;
- When the machine is out of use for a long time, the surface of each part should be cleaned and coated with anti-rust oil.
First class maintenance
- The hydraulic press machine runs for 500 hours for primary maintenance, mainly done by operators, and the maintenance workers cooperate.
- First cut off the power supply and then carry out maintenance (see table below).
|No.||Position||Maintenance details and requirements|
|1||External maintenance||1. Clean the outside surface of hydraulic press, maintain inside and outside clean, no rust.|
|2. Complete the missing screws, nuts, buttons, signs, etc.|
|2||Beam, column guide||1. Clean the outer surface of upper and lower beams and movable beams, as well as pillar, guide rail, slide block and press plate. Clean without oil, yellow robe and rust stain.|
|2. Remove the burrs on the bottom surface of the movable beam and the upper surface of the lower beam as well as on the pillar, guide rail and slider.|
|3. Check and tighten the fasteners of the beam and column guide rails.|
|3||Hydraulic, lubrication||1. Wipe and check the surface of oil pump, valve, oil tank and pipeline, clean, rust free, oil free, no yellow robe, no leakage.|
|2. Clean the oil cup, filter screen, dredge the oil road, the oil mark is clear.|
|3. Check the oil quality and quantity in the fuel tank, add lubricating oil as appropriate.|
|4. Check gauge|
|5. Check the lubrication of columns and guide rails.|
|4||Electric||1. Clean the electrical box without dirt or grease.|
|2. Check the integrity of the line, hose protection connection reliable, good performance.|
|3. Check the travel switch of movable beam, check whether the action is sensitive and reliable.|
|4. Safety protective cover, pillar protective cover complete and easy to use, foot pedal switch protective cover intact, safe and reliable.|
|5. Check and tighten the zero connecting device.|
|No.||Position||Maintenance details and requirements|
|1||Beam, column guide||1. Check and adjust the horizontal plane of the beam, guide rail, guide sleeve, slide block and press plate of the column so as to achieve smooth movement and meet the technical requirements.|
|2. Repair or replace defective parts.|
|2||Hydraulic, lubrication||1. Disassemble and repair solenoid valve, grinding valve and valve core.|
|2. Clean and inspect oil pump, cylinder and plunger, repair burrs and replace oil seal.|
|3. Check pressure gauges.|
|4. Repair or replace badly worn parts.|
|5. Start the hydraulic press machine to check whether the movement of each cylinder and plunger is smooth, no crawling. Check whether the support valve can stop the moving beam in any position accurately and the pressure drop meets the process requirements.|
|3||Electric||1. Clean motor, check bearing and replace grease.|
|2. Repair or replace damaged components.|
|3. The electrical appliances meet the requirements of the equipment standard.|
|4||Accuracy||1. Calibrate machine tool level, check, adjust and repair accuracy.|
|2. Accuracy in accordance with the equipment integrity standards.|
Hydraulic Press Machine Troubleshooting
You can check out the common faults and troubleshooting solutions for hydraulic press machine in our previous written article.
Hydraulic Press Safety Rules
- Those who do not understand the hydraulic press machine structure performance or operating procedures should not start the machine without permission.
- The machine should not be overhauled or adjusted during operation.
- When finds serious oil leakage or other abnormality in the hydraulic press (such as unreliable operation, loud noise, vibration, etc.), it should be stopped and the operator should analyze the reason and try to eliminate it.
- Do not use if an overload or exceed the maximum eccentricity
- It is strictly prohibited to exceed the maximum stroke of the slider, and the minimum closing height of the mold shall not be less than 600mm.
- The grounding of electrical equipment must be firm and reliable.
- At the end of each day, put the slider to the lowest position.
Hydraulic Press Tonnage Calculations
With the development of industry and the progress of hydraulic technology, the hydraulic press is used more and more widely in industrial production.
Whether you are a manufacturer or user of a hydraulic press, it is important to know how to calculate hydraulic press tonnage.
As a professional manufacturer, we will tell you how much force does a hydraulic press exert and how important it is.
To know the tonnage of the hydraulic cylinder, the first thing you need to know is the hydraulic system working pressure, and the hydraulic cylinder inner diameter and the outer diameter of cylinder rod (it will be needed when calculating the tensile force of hydraulic cylinder).
The equation for hydraulic press tonnage calculation formula:
If hydraulic cylinder inner diameter = 10cm, working pressure = 16MPa (160kgf)
Hydraulic cylinder inner section area = 3.14×10×10÷4=78.5cm2
Pushing force = 78.5×160=12560kg=12.56Ton
In order to make it more easily, we make following hydraulic press tonnage calculator:
Through this formula, we can easily calculate the tonnage of the hydraulic press we purchased or we needed, and avoid buying equipment with low tonnage at the high price.
At the same time, we can calculate the working pressure of our own hydraulic press by this formula, so as to avoid the overload operation of the equipment and improve the service life and performance of the hydraulic press.
Buying Guide for Hydraulic Press Machine
Before you buying your hydraulic press machine, you must be wondering what exactly size hydraulic press do you need. I believe this problem can be easily solved if you use above mentioned hydraulic press tonnage calculation formula.
Then, where to buy the hydraulic press?
Many people will get confused at this point. You have many reasons to buy in different places. And there’s a lot of good hydraulic press machine manufacturer around the world. However, the most cost-effective hydraulic press machine must be produced by China hydraulic press manufacturer.
Spend some time to find the most reliable and satisfied hydraulic press manufacturer, then you will get all the detailed specifications and cost of your desired hydraulic press.
Hydraulic Press Crushing Things
Many people would like to know things that can be crushed by a hydraulic press or things that can resist hydraulic press. I think this should be considered based on different tonnage of the hydraulic press.
If you have a hydraulic press in your workshop, you can have a test and find out the result.
Maybe someday in the future, we will also try this out.
Hydraulic Press Terminology
Here we list 7 commonly used terminology for hydraulic press operation, the experienced engineers and operators must know all of them, but the new guy must don’t. Let’s dive into it.
The highest pressure at which a machine can be used continuously.
The sealing of the relative sliding part of the hydraulic press becomes a motive seal.
Hydraulic system circuit diagram represented by professional graphic symbols.
Hydraulic drive system
The hydraulic transmission device is a device that converts pressure of fluid into power.
Hydraulic pressure station
A hydraulic device consisting of a fuel tank, a hydraulic pump, a motor, a control valve, etc.
The weight carried by balancing the pressure of the liquid, including the equipment of the hydraulic press itself.
The return of oil from a pipe in a hydraulic device to a tank or a collector is called oil drain.
Difference Between Mechanical Press and Hydraulic Press
Hydraulic press drawing refers to positioning the blanking part in the mold when the hydraulic press is in the process of drawing, the blanking ring controls the flow of metal to form the hollow workpiece.
Generally speaking, deep drawing refers to the workpiece whose depth exceeds 1/2 of its diameter.
The blanking of the punching machine is made into the desired shape by cutting and punching the plate. The material can be a single sheet or a continuous long strip.
Stamping can be blanking, but it also includes forming, bending, flanging, hole punching processes.
If the drawing process is added to the punch machine on the basis of the blanking, the press can be called hydraulic punch press.
Generally speaking, the punching machine has a simple structure, fast production speed and high efficiency. It is suitable for large quantity and simple blanking forming.
And the hydraulic press is suitable for the production of the medium and small batch, there is a requirement for accuracy and depth, changeable shape, have precise requirements for the slider velocity, pressure and position, fabrication according to the order.
Therefore, when customers choose to purchase processing machinery, they should choose a suitable hydraulic press or mechanical press according to the actual processing demand.
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