When using press brakes for manufacturing precision and power go hand in hand. One crucial aspect that determines the effectiveness and efficiency of bending operations is press brake tonnage and force. Whether you’re a seasoned professional or just beginning industrial metalworking, comprehending these concepts is essential for achieving optimal results. In this blog, we look into what press brake tonnage and force entail, their significance, and how they impact the bending process.

What is Press Brake Tonnage?

Press brake tonnage refers to the amount of force exerted by a press brake during the bending process. It’s a measure of the machine’s capability to bend a specific material thickness and type. Tonnage represents the maximum force the press brake can apply to the workpiece. The Delem software, like that found on our Genius Pro series of press brakes, comes ready to help automate calculations.

Understanding Force in Bending:

When a press brake bends a metal sheet or plate, it applies force to deform the material. This force is transmitted through the upper punch and lower die, collectively known as tools or tooling of the press brake. The amount of force required depends on various factors, including:

  • Material Type: Different metals have varying strengths and elasticity, which influence the amount of force needed for bending. For instance, bending stainless steel typically requires more force compared to bending aluminum of the same thickness.
  • Material Thickness: Thicker materials require higher tonnage to bend effectively. As the thickness increases, so does the resistance to deformation, necessitating greater force.
  • Bend Angle: The angle at which the material is bent also affects the required force. Sharp bends or tighter radii demand more force than gradual bends.
  • Tooling Selection: The selection of appropriate tooling, including punches and dies, is crucial in determining the force distribution during bending. Proper tooling ensures uniform bending and reduces the risk of material distortion.

Importance of Correct Tonnage:

All press brakes sold from Moore Machine Tools include a handy magnetic tonnage chart for operator use.

Using the correct press brake tonnage is paramount for several reasons:

  • Avoiding Material Damage: Insufficient tonnage can lead to incomplete bends or material damage, such as cracking or buckling. Conversely, excessive tonnage may cause over-bending, resulting in inaccuracies or material deformation.
  • Ensuring Accuracy: Proper tonnage ensures accurate bending according to the desired specifications, including bend angle and dimension. This is crucial, especially in industries where precision is non-negotiable, such as aerospace or automotive manufacturing.
  • Enhance Tooling Life: Overloading the press brake with excessive tonnage can accelerate wear and tear on tooling components, reducing their lifespan. Using the correct tonnage extends the longevity of tooling and reduces maintenance costs.

Calculating Required Tonnage:

Determining the required tonnage for a bending operation involves considering several factors:

  • Material Type and Thickness: Understand the material’s properties, including its tensile strength and thickness.
  • Bend Length: The length of the bend influences the distribution of force along the material.
  • Bend Angle: Sharper angles typically require higher tonnage compared to gentler bends.
  • Material Support: Ensure proper material support and alignment to prevent deflection and inaccuracies.

The formula is as follows:

P=650S²L/V (σb=450N/mm²)


P=Bending force

S=Thickness of metal plate

V=Opening of the bottom die

B=Min bending flange

R=Inside radius


Press brake tonnage and force are critical parameters in metal bending operations, influencing the quality, accuracy, and efficiency of the process. By understanding the relationship between material properties, bending parameters, and tonnage requirements, fabricators can optimize their manufacturing operations for superior results. Investing in the right equipment, tooling, and expertise ensures that each bend meets the highest standards of precision and quality. By working with Moore Machine Tools, you are setting yourself up for future success in your industrial machinery needs.