High Tonnage Press Brakes: The Key to Enhanced Manufacturing Efficiency

In the competitive landscape of modern manufacturing, efficiency is paramount. One of the key players in achieving enhanced productivity is the High Tonnage Press Brake. Designed to handle heavy-duty metal forming tasks with precision and speed, these machines are essential for industries that require robust solutions for complex fabrication needs. As manufacturing processes evolve, high tonnage press brakes not only streamline operations but also elevate the quality of finished products. This article explores how these powerful machines are transforming the manufacturing sector, highlighting their advantages, applications, and the factors to consider when integrating them into production lines.

What Is Press Brake

Press brakes are essential machines used in metal fabrication to bend and form sheet metal into various shapes and angles.

The basic working principle of a press brake is straightforward: a sheet of metal is placed on a bottom tool called the die, and an upper tool called the punch presses down on the sheet with great force, causing the metal to bend and conform to the shape of the die.

Due to their ability to shape metal components precisely, press brakes are highly versatile and are used in a wide range of industries. Some common applications include:

In the automotive industry, press brakes are used to form body panels, frames, brackets, and other structural parts.

The aerospace sector relies on press brakes to fabricate fuselage sections, wing components, engine enclosures, and more.

Construction and infrastructure projects use press-bent parts, such as structural steel sections, roofing panels, and HVAC ductwork.

Press brakes also produce components for electronics, medical equipment, home appliances, furniture, and many other products we use every day.

What Is Press Brake Tonnage?

Press brake tonnage refers to the maximum force or bending capacity that a press brake can exert to bend a metal plate. This tonnage is crucial for achieving precise bending angles in fabrication processes.

The tonnage rating of a press brake determines the maximum force it can apply to the metal, ensuring accurate bends. It’s important to note that the actual working tonnage should never exceed the machine’s rated capacity or the maximum load that the die can handle.

Selecting the correct tonnage is essential to prevent common issues such as tool damage, inaccurate bends, and insufficient force for the required operations.

Several factors influence the actual tonnage needed, including the bending radius, bending method, thickness of the material, tensile strength, die ratio, friction between the material and the die, the rolling direction of the steel, and work hardening.

In general, thicker and harder sheet metals require higher tonnage for bending, while thinner materials necessitate lower tonnage. Understanding these parameters helps ensure optimal performance and longevity of the press brake.

The force applied by a press brake to the material is measured in tonnage, which is vital for achieving accurate and consistent bends. Tonnage represents the maximum force that a bending machine can exert to shape a metal plate, typically expressed in tons per foot or kilonewtons per meter.

Each press brake has a specific tonnage rating that indicates the maximum force it can generate. Selecting the right tonnage for each application is crucial to avoid damaging the machine, tools, or materials involved.

Calculating press brake tonnage primarily depends on several factors, including the thickness of the metal plate, the bending length, and the width of the V-shaped opening. A press brake tonnage calculator can assist in determining the force needed for specific tasks.

It’s important to be familiar with the various units of measurement used to express tonnage capacity, as different calculation methods may apply. For instance, a standard formula for tonnage calculation might use AISI 1035 cold-rolled steel with a tensile strength of 60,000 PSI as a reference.

In addition to tonnage, other elements such as die angle, K-factor, and tool compatibility are critical for achieving precise and smooth bends. These factors should be considered when setting up and operating the bending machine to ensure consistent results and maintain the efficiency of the bending process.

There are multiple methods for measuring press brake tonnage, and understanding the most commonly used units of measurement is an essential first step. Tonnage can be calculated using a formula that incorporates material thickness, bending length, and the width of the V-shaped die opening. This formula can be paired with tonnage charts or calculators to estimate the required bending force.

Choosing the appropriate press brake tonnage is essential to prevent tool damage or excessive force that could harm the worktable or ram. Additionally, the sinking tonnage limit refers to the time required for the punch to embed into the base or ram of the press brake, considering the “power flow” through the tool and the maximum tonnage applied per foot or inch of load.

What Is High Tonnage Press Brake

1. Definition and Capacity

• What It Is: A big tonnage press brake is a machine designed to apply a high amount of force to bend or form metal sheets. The tonnage rating indicates its maximum bending capacity, usually ranging from 100 tons to over 1,000 tons.
• Application: Typically used in heavy industries like aerospace, automotive, and construction, where thick and heavy materials need precise bending.

2. Key Components

• Ram and Bed: The ram applies pressure downward, while the bed supports the workpiece. In high tonnage models, both are engineered for durability and strength.
• Die and Punch: The tools used to create specific bends. Larger tonnage machines may accommodate larger dies for complex shapes.

3. Factors Influencing Tonnage Requirements

• Material Thickness: Thicker materials require higher tonnage.
• Bending Length: Longer bends may also necessitate more force.
• Material Type: Different materials (steel, aluminum, etc.) have varying tensile strengths, affecting the required tonnage.
• Angle et rayon de courbure: Sharp bends generally require more force than gentle curves.

4. Calculating Tonnage

• Formula: The basic formula for calculating tonnage is: Tonnage=(MaterialThickness×BendingLength×TensileStrength)ConstantTonnage = \frac{(Material Thickness \times Bending Length \times Tensile Strength)}{Constant}Tonnage=Constant(MaterialThickness×BendingLength×TensileStrength)​
• Constant: This constant varies based on the die design and other factors.

5. Importance of Proper Tonnage Selection

• Preventing Damage: Using the correct tonnage helps avoid damage to the machine and tools.
• Ensuring Quality: Adequate force ensures precise bends and reduces the risk of defects.

6. Operational Considerations

• Setup: Properly setting up the machine is crucial, including die alignment and adjusting for material properties.
• Safety: High tonnage machines require strict adherence to safety protocols due to the substantial forces involved.

7. Entretien

• Regular Checks: Routine maintenance is vital to keep a big tonnage press brake in optimal condition, including lubrication and inspection of components.
• Operator Training: Skilled operators should be trained to handle the complexities of high-tonnage operations safely and efficiently.

What Defines a High Tonnage Press Brake?

Criteria for size and capacity

Bearing capacity: large press brake boosts for its high bearing capacity. This means it can bear and process more extensive and thicker metal sheets. This ability is usually measured by tonnage. The tonnage of a large press brake is usually 1000 tonnage or more, which is heavier than the common press brake type.

Working length: except for bearing capacity, the working length is also essential for verifying whether the press brake is of a large type. The large press brake usually has a longer worktable and bending length, usually 4 meters or more. This allows for easy access to more extensive materials.

Machine size: the giant machine looks tremendous in volume and is usually 6 meters or more long. This not only contains the workbench length for matching large workpieces but also contains the height and width of the machine, making them occupy more space.

Working speed: the large press brake’s working speed is ten beats per minute or faster, improving the working efficiency.

Key features of large-scale press brakes

High-level control system: in order to deal with material of considerable size and high bearing capacity, the large press brake is usually equipped with a control system. These systems can offer more precise bending angle, pressure, and speed control.

Multi-axes back gauge system: the large press brake is usually equipped with a multi-axes back gauge system, which is of vital importance to handling large material. This system can ensure the precise position during the bending process.

Strengthened stability and durability: because of heavier loading, the large press brake pays more attention to stability and durability when designed. This means larger materials can be handled.

Custom function: the large press brake is usually custom-made according to the specific industrial application. This includes special tools, an expanded workbench, and specific software equipment.

Biggest Tonnage Press Brake in the World

Until 2023, Ursviken Technology has sold the industry’s biggest press brake ever produced.

This machine is famous for its tremendous size and advanced function, which proves the technology innovation in the metal manufacturing sphere.

Its bending force is 5000 tons, and its bending length is 73 ft, making it very easy to handle highly demanding bending tasks.

The advancement of the press brake not only lies in its size but also improves its ability to bend larger and thicker metal sheets.

It utilizes the advanced power and control system to improve efficiency. It is equipped with the most advanced automatic technology, including automatic upper die replacement, changing dies, and utterly programmable back gauge, thus improving production, precision, and convenient operation.

Besides, it is equipped with an advanced CNC system, which can improve flexibility and controllability during the bending and forming process.

Moreover, owing to its energy-saving design, it simplifies the working process and saves the cost. Also, safety is critical, and it is equipped with advanced safety functions.

The biggest global press brake not only shows cutting-edge engineering technology but also highlights the globality of manufacturing.

Although the machine is made in Sweden, it impacts the world, including America, which owns the advanced and strong manufacturing equipment.

Factors that Influence Press Brake Tonnage

Bending Method

Different metal bending methods require different tonnage. For example, in air bending, the tonnage can be increased or decreased by changing the die opening width.

The bending radius affects the opening width of the die. In this case, a method factor must be added to the formula. When using the bottom bending and coining methods, the required tonnage is higher than that of air bending.

If the tonnage for bottom bending is calculated, the tonnage per inch of air bending needs to be multiplied by at least five times. If coining is used, even more tonnage may be required than for bottom bending.

Die Width

We have learned that in air bending, the tonnage required decreases as the die opening size increases and increases as the opening size decreases.

This is because the width of the die opening determines the internal bending radius, and a smaller die radius requires more tonnage.

In air bending, the die ratio is typically 8:1, meaning that the die’s opening distance is eight times the material thickness. At this point, the material thickness is equal to the internal bending radius.

Friction and Speed

In air bending, the punch needs to pass over the opening of the bottom die to bend the sheet metal.

If the surface of the metal plate is not lubricated, the friction between the die and the sheet metal will increase, requiring more tonnage to bend the sheet metal and reducing the material’s springback.

Conversely, if the sheet metal surface is smooth and lubricated, the friction between the die and the sheet metal will be reduced, resulting in lower tonnage required for bending the sheet metal. However, this will increase the sheet metal’s spring back.

The bending speed also affects the tonnage required. As the bending speed increases, the tonnage required decreases.

Increasing the speed can also reduce the friction between the die and the sheet metal, but this will also increase the sheet metal’s springback.

Material Thickness, Tensile strength, and Bending Length

Tonnage is the force applied by the press brake to the metal plate. Therefore, the range of a bending force is determined by the thickness and tensile strength of the sheet metal being bent.

One factor is the type of bending material. Different materials have different tensile strengths, which directly affect the amount of force required to bend them.

For example, stainless steel typically requires more tonnage than mild steel or aluminum. Tensile strength refers to the maximum stress that a material can bear under a steady load. If this stress is applied and maintained, the material will eventually break.

Another important factor is the thickness of the metal plate. The greater the thickness of the material, the greater the tonnage required, and vice versa.

The table shows:

1. As material thickness increases, the required tonnage increases significantly for all materials. Doubling thickness from 1mm to 2mm quadruples the tonnage.
2. Aluminum requires about 45% of the tonnage compared to mild steel of the same thickness, while stainless steel needs about 45% more tonnage than mild steel.
3. Decreasing the inside bend radius while keeping thickness constant increases the required tonnage. Halving the radius from 2mm to 1mm increases tonnage by 50%.
4. The tonnage multiplier varies by material type and tensile strength. It is 1.0 for mild steel, 0.45 for aluminum 5052-H32, and 1.45 for 304 stainless steel in this example.

The bending length of the press brake workbench is the maximum length that the metal plate can be bent. The bending length of the press brake should be slightly longer than the material to be bent.

If the length of the workbench is incorrect, the die or other components may be damaged. The bending load calculator can help determine the required tonnage based on the thickness of the material and other factors, such as bending length and V-shaped opening width.

Tooling Factor

The press brake punch is also a factor to be considered. These punches also have press brake load limits. Right-angle Vee punches can bear a large tonnage load.

Due to the slight angle and fewer materials used in the manufacture of acute angle dies, such as gooseneck dies, they are not inclined to withstand heavy loads.

When using different dies, their maximum bending force must not be exceeded. In addition, the mold radius and bending radius also affect the tonnage requirements.

A larger mold radius may result in an increase in the required bending force. Similarly, larger bending radii may result in higher tonnage requirements.

The ratio between the width of the mold opening and the thickness of the material is another factor that needs to be considered. For thinner materials, it is recommended to use a lower mold ratio (e.g. 6 to 1).

Thicker materials may require a higher mold ratio (such as 10 to 1 or 12 to 1) to reduce bending force and maintain the application within the capacity of the bending machine.

Advantages of High Tonnage Press Brake

1. Increased Bending Capacity

High tonnage press brakes are specifically engineered to handle substantial thicknesses and weights of materials. This makes them indispensable in industries such as aerospace, where components often require robust materials that standard machines cannot handle. The ability to bend thicker plates without compromising accuracy opens up possibilities for more complex designs and applications.

2. Enhanced Precision

Precision is crucial in metal fabrication, especially when producing components that must fit together seamlessly. High tonnage press brakes provide excellent control over the bending process, allowing operators to achieve precise angles and consistent results. Advanced control systems and features like back gauges further enhance accuracy, minimizing the risk of defects and rework.

3. Higher Productivity

With their powerful capabilities, high tonnage press brakes can execute complex bends more rapidly than lower-tonnage alternatives. This efficiency leads to reduced cycle times, meaning more parts can be produced in a shorter timeframe. As a result, manufacturers can meet tight deadlines and fulfill larger orders without compromising quality.

4. Versatility

High tonnage press brakes can work with a variety of materials—steel, aluminum, brass, and more—making them adaptable for diverse applications. Their ability to handle different shapes and sizes means they can accommodate a wide range of projects, from simple bends to intricate designs, thus serving multiple functions within a manufacturing facility.

5. Improved Tooling Options

The robust construction of high tonnage press brakes allows for the use of larger and more complex dies. This flexibility enables manufacturers to produce intricate shapes that might not be feasible with standard machines. Additionally, larger dies can enhance productivity by reducing the number of setups required for various bending tasks.

6. Reduced Tool Wear

Using the appropriate tonnage reduces strain on tools, leading to longer tool life and lower maintenance costs. High tonnage press brakes can apply the necessary force without excessive pressure that could lead to tool damage. This durability minimizes downtime and enhances overall operational efficiency.

7. Consistency and Reliability

Manufacturers depend on consistency for quality assurance. High tonnage press brakes are designed to deliver reliable performance, ensuring that each bend meets stringent specifications. This consistency reduces variability in production, which is essential for maintaining product standards and customer satisfaction.

8. Cost-Effectiveness

Though the initial investment in high tonnage press brakes may be significant, the long-term benefits often outweigh the costs. Increased efficiency, reduced scrap rates, and longer tool life contribute to overall savings. Additionally, the ability to take on larger and more complex projects can lead to increased revenue opportunities for manufacturers.

9. Safety Features

Modern high tonnage press brakes come equipped with advanced safety features, such as automatic shutoff systems, light curtains, and protective guards. These features not only protect operators but also help prevent costly accidents that could lead to downtime or damage to the machine.

10. Technological Advancements

Many high tonnage press brakes are now integrated with cutting-edge technology, including CNC controls and automation capabilities. These advancements facilitate more complex bending tasks and can integrate seamlessly into smart manufacturing environments. As a result, manufacturers can leverage data analytics and real-time monitoring to optimize production processes and improve decision-making.

11. Reduced Environmental Impact

High tonnage press brakes can also contribute to sustainability efforts in manufacturing. By maximizing material utilization and reducing scrap, these machines help minimize waste. Additionally, modern models often feature energy-efficient designs, which can reduce overall energy consumption during operation.

By harnessing these advantages, high tonnage press brakes not only enhance the efficiency and quality of metal fabrication processes but also position manufacturers to adapt to the evolving demands of the market. Their capabilities make them an essential tool for any serious metalworking operation.

Choosing the Correct Press Brake

When selecting a press brake, it is essential to consider the type of material to be bent, along with its specifications, length, and processing method. These factors directly influence the required tonnage and dimensions for your specific project.

Determining the correct tonnage is crucial, as it significantly impacts the overall performance and bending capacity of the machine. To calculate the appropriate tonnage, you can utilize a press brake tonnage calculator, which factors in the thickness of the metal plate, bending length, and the recommended width of the V-shaped die opening.

Another key consideration is the length of the workpiece. The machine’s size must accommodate the required length to ensure efficient and accurate bending. It’s vital that the length of the workpiece does not exceed the maximum capacity of the machine.

Finally, you should take into account the machine’s tonnage limit in relation to the distance between the side frames. Exceeding the permissible distance could lead to damage, as it would surpass the machine’s centerline load limit. Being mindful of these specifications will help ensure that you choose the right press brake for your needs.

When Do You Need A High Tonnage Press Brake

A high tonnage press brake is essential in various scenarios within metal fabrication. Here are some situations where investing in this type of machine is beneficial:

1. Working with Thick Materials

• If your projects involve bending thick metal sheets, a high tonnage press brake is necessary to apply the substantial force required for accurate bends. Standard machines may struggle or fail to handle these materials effectively.

2. Heavy-Duty Applications

• Industries such as aerospace, automotive, and construction often require robust components made from heavy materials. High tonnage press brakes are designed to meet these demanding needs, ensuring that critical parts are fabricated correctly.

3. Complex Bending Requirements

• When dealing with intricate designs that necessitate precise bends, a high tonnage press brake can provide the control and force needed to achieve high-quality results. This is particularly important for parts that must fit together seamlessly.

4. High Production Volumes

• For manufacturers that operate on a large scale, investing in a high tonnage press brake can enhance productivity. These machines can handle larger batches efficiently, reducing cycle times and increasing overall output.

5. Material Variety

• If your projects require working with different types of materials (e.g., various alloys or grades of steel), a high tonnage press brake offers the versatility to handle diverse specifications, adapting to different tensile strengths and thicknesses.

6. Increased Precision Needs

• For applications where precision is paramount, such as in high-tech industries, a high tonnage press brake can ensure that the necessary accuracy is maintained across multiple bends and pieces, reducing the risk of defects.

7. Custom Fabrication Projects

• When working on custom or one-off projects, high tonnage press brakes provide the capability to create specialized parts that may not be feasible with lower-tonnage machines.

8. Long Bending Lengths

• If your workpieces are particularly long, a high tonnage press brake can accommodate the required bending length while maintaining the necessary force and precision.

9. Future Growth and Scalability

• If you anticipate growth in your manufacturing capabilities or an increase in project demands, investing in a high tonnage press brake can provide the flexibility to take on more complex and larger projects in the future.

In summary, if your metal fabrication work involves heavy materials, intricate designs, high production volumes, or a need for precision and versatility, a high tonnage press brake is an essential tool to meet those demands effectively.

High tonnage and big thickness bending with your press brake

We want to publish a useful and interesting article about big thickness bending that we can show to our potential customers. Without the necessity to explain every time, we decided to make this article with all the important notes.

This way, we will speak about bending of big thicknesses or bending of special steels like Hardox®, Raex®, Domex®, Weldox®, DOCOL®, Raex®, Optim®, Ramor®, and other high-resistant, hardened, wear-resistant steels with a high tensile strength value.

One time, we had a case:

The customer asked us for some bending tools to bend special steel. Moreover, he already had the quotation on his hands for punch and die, and he requested from us just the competitive offer for the same positions. During the conversation, we discovered that he has an ordinary press brake of around 200 tons for 3 meters, but for his bending work, he needed around 300 tons per meter. So for us, it was impossible to offer any tools, and we told the customer that there was no solution. Also, it was really strange that our competitor, a very well-known company, made such an irresponsible offer.

And the problem is very common: customers do not understand the possibilities and limits of their press brakes, and they do not understand what the main problem is for us to decline the request.

Steps by steps for big thickness bend

The most important detail of the press brake is the available tonnage. Let us make the example that the machine is 100 tons for 3 meters. It is a very typical bending machine in production.

The first question that the customer should understand is the tonnage for the requested length. During any study, we operate with the value of tonnage per meter. And the first question that we can ask is: if you have 100 tons for 3 meters, can you have on your machine 100 tons for 1 meter? Or 100 tons for 500 mm, if necessary? It could be an unanswered question, and there are really limitations with the old machine. So the customer should know what tonnage per length he can achieve.

The second point comes from the model of the press brake. Each tooling system has its limitations. If you overload the limitations and have strong bending tools for high tonnage, you have the risk of damaging the holders.

Press brake tonnage for the length

Let us set an example. The standard Promecam tooling system has a limit of 100 tons per meter for punch holders. If you make more, you will destroy the intermediates. If you have no intermediates, you can damage the beam. The reason is simple: the force is transferred through the piece with a width of 13 mm. It is not so big to transport the bigger tonnage.

The customer, let us consider, has the press brake of 220 tons for 3 meters. Maybe he can bring 220 tons even for 1 meter, and the manufacturer of the press brake confirms this possibility. But he cannot because his holders are limited to 100 tons per meter!

It is absolutely important that if the bending is not done at  full length and requires a large tonnage, it be done strictly at the center of the machine. Otherwise, you will have the risk of the beam inclination, which leads to unparallelity.

So what do we have? A lot of customers think that their machine tonnage is their possibility for everything, even for 50 mm, and they can do everything. It is a completely wrong position, which could lead to a lot of risks for the machine and the operator itself.

To avoid risks at all costs

Even if the customer wants it, it is more appropriate to decline the project if we have doubts and see the risks. One more time, overtonnage could lead to:

• Punch deformation and damage
• Die deformation and damage
• Holders damages
• Beam damages

Let us just imagine that it is good if the punch during the overtonnage is just a little bit compressed and the machine is stopped after. But damage to the holder could lead to the risk of misplacement of the punch, and it could also hit the operator. So we are not talking only about the risks of the machine but also about the health and even the life of the operator.

We also do not know how the particular customer is prepared. Sometimes we have a lot of basic questions, and we can decide that the customer is not prepared at all. So we cannot be sure that he understands all the risks and takes all the measures and actions to prevent any problems.

But in a lot of cases, there is one big risk: there is no solution. The customer will not make the bend what he wants. He doesn’t have the proper capacity to do the job, so even if he is ready to invest, he probably needs to invest in the new press brake. There is no alternative solution!

There is one common risk as well: the customer declines to believe that he did something wrong. It is very easy to deform the gooseneck punch due to the overtonnage. It will just bend more. But for customers, it is easy to think that it is just the poor quality of the tool itself. So for us, it is better to decline the job near the limits.

Problems of design for the part

The design of the part becomes highly important if there are big thicknesses and small sizes together! For 1 mm thickness, you have a lot of freedom, and you can send the production drawing now to any machine to perform the bending. But if we are talking about critical values, the additional preparations are very important.

One case from our experience: the customer brang the part drawing to supply the tooling with special steel bending and a very small flange size. If you have in your workshop the press brake of 1000 tons for 6 meters, you are probably free to design what you want. But if you go to the weaker machines, you can see that such a part is just impossible to do! To respect the dimensions, you need incredible big tonnage, or you need to change the dimensions completely!

Moreover, it is important for special steels. A lot of steel manufacturers have their own recommendations and restrictions for bending. It is the minimal radius to have, and it is the recommended opening of the die to proceed. If the recommended radius is 3S (where S is the thickness of the part) and you have a drawing of 1S, you are automatically going against the recommendations of the steel producer. And any suggestions from the tool supplier are useless because the producer of steel didn’t confirm such a way of bending. So it is recommended for all special steels to have and to verify with the correct technical requirements from the steel producer.

Our recommendations for the customer for big thickness bend

The bending with high tonnage has a lot of risks. There could be a reputable risk that you take on the bending work and cannot do it. But there are a lot of risks to damaging your press brake as well. And problems with the beam could lead to very serious repairs and very big losses for service technicians.

Moreover, the factories do not have press brakes in perfect condition, as they came yesterday from the manufacturer. All the machines are used, all the machines passed intervals from the last service, and all the parts are in used condition with some wear. It means that it is probably better not to use the complete tonnage of your machine but not to overrun up to 80% of its capability.

To bend the thick material, you need to know your machine and its limits perfectly. You need to know the limits not only for the capacities of the press brake but also how the tooling system is made and what the risks are to it. Just for interest, you can see on YouTube how thick materials and special steels are bent. What press brakes are used, and what do the bending tools look like.

Factories buy very expensive high-tonnage press brakes not because they want to throw the money away but because they are necessary for their applications. But sometimes customers with ordinary low- and medium-tonnage machines think that they can also try to bend the same parts. And sometimes it could be possible, but it requires very careful study of everything. Moreover, we recommend also inviting the engineer for such projects because sometimes it is quite important to make modifications to the size of the final part.