How to Calculate Press Brake Tonnage for Different Tooling 

— Tooling Formula & Tonnage Chart

Press brake tonnage is calculated based on material thickness, material strength, die opening, and bending length.

For air bending, the standard formula is:

T=1.42×σ×t2VT = \frac{1.42 \times \sigma \times t^2}{V}

T=V1.42×σ×t2​

Where:

• T = tonnage per meter (kN/m)
• σ = tensile strength of material (N/mm²)
• t = material thickness (mm)
• V = die opening (mm)

In simple terms:

• Thicker material requires more tonnage
• Smaller V opening requires more tonnage
• Stronger material requires more tonnage

This formula is commonly used when selecting:

• heavy duty press brake dies
• multi V press brake dies
• large V opening press brake die

Smaller die openings and thicker materials dramatically increase bending tonnage.

Why Press Brake Tonnage Matters

Correct tonnage calculation helps manufacturers:

• Prevent machine overload
• Avoid tooling breakage
• Improve bending accuracy
• Extend tool life
• Reduce production cost

Incorrect tonnage selection can cause:

• Cracked punches
• Damaged dies
• Machine deflection
• Poor bending angles

Press Brake Tonnage Formula Explained

1. Material Thickness

Tonnage increases exponentially with thickness.

Example:

Because thickness is squared in the formula.

2. Die Opening (V Opening)

The V opening directly affects tonnage.

A large V opening press brake die reduces bending force and machine load.

This is ideal for:

• aluminum sheets
• thin sheet metal
• large radius bending

3. Material Type

Different materials require different tonnage.

Example:
If mild steel needs 50 tons, stainless steel may require 75 tons.

Tonnage Differences by Tooling Type

Heavy Duty Press Brake Dies

Best for:

• thick plate bending
• structural steel
• high tonnage applications

Keywords naturally included: heavy duty press brake dies

Characteristics:

• reinforced body
• high load capacity
• smaller V options

Advantages:

• high durability
• suitable for thick material
• better load resistance

Disadvantage:

• higher tonnage demand

Typical applications:

• truck chassis
• construction parts
• industrial cabinets

Multi V Press Brake Dies

Keywords naturally included: multi V press brake dies

Multi V dies contain several V openings in one tool.

Benefits:

• one die for multiple thicknesses
• reduced setup time
• lower tooling inventory cost

Applications:

• job shops
• flexible manufacturing
• small batch production

Example:
A single multi V die may include:

• 16 mm
• 22 mm
• 35 mm
• 50 mm V openings

This allows operators to optimize tonnage quickly.

Large V Opening Press Brake Die

Keywords naturally included: large V opening press brake die

Large V dies are ideal for:

• soft materials
• cosmetic parts
• no-mark bending

Advantages:

• lower tonnage
• larger bend radius
• reduced tool wear

Best for:

• HVAC panels
• enclosures
• appliance parts

Example Press Brake Tonnage Calculation

Material: Mild steel
Thickness: 3 mm
V opening: 24 mm

Formula:

T=1.42×450×3224T = \frac{1.42 \times 450 \times 3^2}{24}T=241.42×450×32​

Result:

≈ 24 kN/cm

This equals approximately:

240 tons/meter

(Actual values vary by machine and tooling geometry.)

Recommended Die Selection Rule

A common rule:

V opening = 6× to 8× material thickness

Examples:

For thick materials, choose heavy duty press brake dies.

For flexible production, choose multi V press brake dies.

For lower tonnage and smoother bending, choose large V opening press brake die.

Accurate press brake tonnage calculation is essential for safe and efficient bending.

Choosing the right tooling matters:

✅ Heavy duty press brake dies for high tonnage and thick plate
✅ Multi V press brake dies for flexible production
✅ Large V opening press brake die for lower tonnage and larger radius bending

At BENDMAX, we supply high-precision press brake tooling designed for:

• durability
• accuracy
• compatibility with major press brake systems

Contact us for tooling recommendations and custom bending solutions.

FAQ: Press Brake Tonnage Calculation

How do I calculate press brake tonnage?

Use this formula:

T=1.42×σ×t2VT = \frac{1.42 \times \sigma \times t^2}{V}T=V1.42×σ×t2​

Tonnage depends on:

• thickness
• material
• die opening

Does a larger V opening reduce tonnage?

Yes.
A larger V opening reduces required bending force but increases bend radius.

This is why a large V opening press brake die is used for low-force bending.

What tooling is best for thick plate bending?

For thick materials, use heavy duty press brake dies because they offer:

• higher load capacity
• better structural strength
• reduced deformation

Why use multi V press brake dies?

Multi V press brake dies improve efficiency by allowing multiple V openings in one die.

Benefits:

• fewer tool changes
• lower tooling cost
• higher flexibility

Bendmax provides tonnage reference data for each product, which can be used as a guideline when selecting tooling. You can also contact our engineers for professional assistance.