Press Brake Tonnage Calculator

Tonnage refers to the bending pressure required during the bending process. Available models typically range from 30T to 2200T. So, how do you choose the appropriate press brake based on your daily bending workpiece requirements? The selection of the correct press brake tonnage is influenced by factors such as the length, thickness of the sheet, and the width of the lower die opening.

There are 2  methods for calculating the tonnage of a press brake: referring to the Press Brake Tonnage Chart and using the Press Brake Tonnage Calculator formula. Both methods can help you determine the right tonnage based on your material and workpiece specifications.

Of course, the simplest way is that you can calculate using the Press Brake Tonnage Calculator provided at the beginning of this article.

The Press Brake Tonnage Chart provides tonnage values based on the tensile strength and a standard sheet length of L = 1 meter. When bending different sheet materials and lengths, you can use the chart and adjust the values according to the material’s properties. To calculate the required tonnage for other materials, simply multiply the value from the chart by the following coefficients:

The Press Brake Tonnage Chart provides tonnage values based on the tensile strength and a standard sheet length of L = 1 meter. When bending different sheet materials and lengths, you can use the chart and adjust the values according to the material’s properties. To calculate the required tonnage for other materials, simply multiply the value from the chart by the following coefficients:

• Bronze (soft): 0.5;
• 304Stainless steel: 1.5;
• Aluminum (soft): 0.5;
• Chrome-molybdenum steel: 2

Example:

If the sheet thickness is S = 3mm and the length is L = 3m, you can refer to the Press Brake Tonnage Chart. For S = 3mm and L = 1m, the chart indicates P = 250KN.

So, if the length is 3 meters, the total tonnage required is:

250KN×3m=750KN=75Ton

In addition to the Press Brake Tonnage Chart, you can calculate tonnage using a more precise formula based on the V-bending method. The force required to bend metal sheets is determined by the sheet thickness, die opening, bending length, and the material’s ultimate tensile strength. The Press Brake Tonnage Calculator formula can be used to calculate the tonnage with the following standard die ratios:

You can input the die ratio to calculate the die opening, with the following standards as a reference:

• v = 6S, S: 0.5-2.6mm
• v = 8S, S: 3.0-8.0mm
• v = 10S, S: 9.0-10.0mm
• v = 12S, S: above 12mm

When S=3mm，L=3m

P=650 x3² x3/24≈730 KN=73Ton

The result is similar to the value we obtained from the chart.

If the sheet is made of stainless steel, you also need to multiply the result by the material coefficient for stainless steel, which is 1.5:

The total tonnage would be 75Ton x 1.5 = 112Ton.

Assuming the thickest material is 1/4 inch, a 10-foot free bending requires 165 tons, while bending with a bottom die (corrective bending) requires at least 600 tons. If most parts are 5 feet or shorter, the tonnage is almost halved, greatly reducing procurement costs. The length of the parts is very important for determining the specifications of the new press brake.

The choice of press brake tonnage is critical. Selecting either too large or too small a tonnage can result in significant risks.

Many users mistakenly believe that purchasing a high-tonnage press brake will allow them to bend all small workpieces within the required tonnage. However, this is incorrect. The bending tooling for large press brakes is not suited for smaller workpieces. Large press brakes typically use multi-V die bottoms, where the V-shaped gaps are too large for thin sheets. Even if a smaller die is used, the larger press brake’s wider worktable can sometimes affect the bending results. Additionally, using a higher-tonnage press brake means more power consumption, which results in unnecessary energy waste when bending smaller workpieces.

Conversely, if the press brake tonnage is too small, it will not provide enough pressure for effective bending. This can lead to insufficient bending angles, uneven edges, or multiple bends to achieve the desired result, negatively impacting production efficiency.

Conclusion

Whether you use the Press Brake Tonnage Calculator or the Press Brake Tonnage Chart, understanding how to calculate the required tonnage based on your material and workpiece specifications is crucial for optimal press brake performance. By selecting the correct tonnage, you can ensure efficient, accurate, and cost-effective bending operations, while avoiding unnecessary energy consumption or inadequate bending results.

Choose my press brake products based on the calculation method！