Press Brake Capacity Calculator

Example Data Table

Values are illustrative and depend on actual tooling and condition.

Formula Used

This calculator estimates bending force using a widely used press brake approximation:

• Required tons (base) = (K × UTS × t² × L) ÷ (V × 2000)
• Required tons (with safety) = Required tons (base) × Safety factor

Where: UTS is tensile strength (psi), t is thickness (in), L is bend length (in), V is die opening (in), and K depends on the bending method.

Notes: Force rises with thickness squared, and drops as die opening increases.

How to Use This Calculator

1. Select units and material, or enter a custom strength.
2. Choose the bending method used for production.
3. Enter thickness, bend length, and die opening (V).
4. Set a safety factor to cover variability.
5. Optionally add machine tonnage and bed length for checks.
6. Press Calculate to view results above the form.

If utilization is high, reduce length, increase V, or change method.

Practical Notes

• Air bending typically uses less force than bottoming or coining.
• A common starting point is V around 6–8× thickness.
• Long bends can require extra capacity due to deflection.
• Always verify tooling limits and manufacturer recommendations.

Press Brake Capacity Planning Guide

1) Why capacity matters on construction jobs

In construction fabrication, bending errors can delay critical installs. Underestimating force risks damaged tooling, cracked material, and overloaded machines. Overestimating can push crews toward oversized equipment and unnecessary handling steps. A capacity check supports safer setups, predictable cycle times, and cleaner bend quality.

2) Inputs that drive the tonnage calculation

The force estimate depends on thickness, bend length, die opening, and material strength. Thickness has the largest impact because force scales with thickness squared. Bend length increases force linearly. Die opening reduces force when increased, but it also affects inside radius and flange clearance.

3) Typical tensile strength reference values

Mild steel commonly falls near 58,000 psi ultimate strength, while many stainless grades are significantly higher. Aluminum alloys are usually lower, and copper-based materials vary by temper. If you have mill test reports, use the custom strength option for tighter estimates on high-strength plate or specialty stock.

4) Bending method factors and shop reality

Air bending generally requires less force because the material does not fully seat in the die. Bottoming increases force, and coining increases it further. This calculator applies a method factor to reflect those differences, but actual results still depend on punch radius, die angle, lubrication, and surface condition.

5) Die opening selection and bend radius behavior

A common starting point is a V opening around 6 to 8 times thickness for air bending. Smaller V openings can reduce inside radius but increase force sharply and may mark the part. Larger V openings reduce tonnage but can produce a larger radius and require longer flanges to avoid interference.

6) Length, deflection, and crowning considerations

Long bends distribute force across the bed, yet deflection can concentrate load at the center. Crowning systems and segmented tooling help control angle variation. If utilization is near the machine limit, consider shorter hits, staged bends, or tooling changes to reduce peak tonnage and improve repeatability.

7) Safety factor and verification workflow

Safety factor covers uncertainty from material variability, operator setup, and wear. Values between 1.10 and 1.25 are common for planning. Before production, validate with a test bend, confirm punch and die ratings, and follow the machine manufacturer’s tonnage-per-foot guidance for the specific model.

8) Using results for estimates and production readiness

Treat the required tonnage with safety as your planning number. If the calculator reports high utilization, increase die opening, reduce bend length per hit, or select a lower-force method. When planning crews and schedules, pair the tonnage check with handling time, setup time, and tolerance requirements for field fit-up.

FAQs

1) What does “tons per foot” mean?

It is the required tonnage normalized to a 12-inch bend length. It helps compare jobs across different lengths and supports quick checks against machine tonnage-per-foot limits.

2) Why does thickness increase force so fast?

The force term uses thickness squared, so a small thickness increase can raise tonnage dramatically. Always re-check capacity when thickness changes, even if other inputs stay the same.

3) Should I always use the recommended V opening?

No. The recommendation is a starting point. Part geometry, flange length, finish requirements, and radius targets can justify a different V opening, as long as tooling and tonnage limits remain safe.

4) Why can two machines with the same tonnage behave differently?

Frame stiffness, bed length, crowning, control accuracy, and tooling condition affect real performance. Manufacturer charts and maintenance condition matter as much as the nameplate rating.

5) Does inside radius change the tonnage calculation here?

This tool reports an estimated radius for reference, but tonnage is primarily driven by V opening, thickness, length, material strength, and method factor. Use tooling catalogs for precise radius outcomes.

6) What safety factor should I choose?

For planning, 1.10 to 1.25 is typical. Use higher values for unknown materials, worn tooling, long bends, or critical safety concerns. Use lower values only with verified shop data.

7) What if the result says “over capacity”?

Reduce bend length per hit, increase V opening, choose a lower-force method, change material thickness, or move the work to a higher-capacity machine. Always confirm tooling ratings before proceeding.