SIZING TOOL
Press Brake Tonnage & Size Calculator
Estimate the bending force needed for air bending sheet metal and plate, and see which HARSLE press brake series suits your job. Enter material, thickness, bend length and V-die opening below.
Calculate required tonnage
Suggested for this thickness: 48mm —
This calculator estimates air bending force using the standard formula P = 1.42 × tensile strength × thickness² ÷ V-die opening. Bottoming and coining require substantially more tonnage — use the bending method selector for an approximate multiplier only.
Estimated requirement
This calculator is intended as a practical guide only. Final machine selection should also consider tooling, material grade, flange size, bend radius, throat depth, open height, stroke, crowning system and production requirements. Talk to Plasquip to confirm your configuration.
How to work out the V-die opening
The V-die opening is the width across the top of the bottom die. In air bending, this is usually selected based on the material thickness.
| Material thickness | Typical V opening | Example |
|---|---|---|
| 1–3 mm | 6 × thickness | 3 mm plate → 18 mm V |
| 4–8 mm | 8 × thickness | 6 mm plate → 48 mm V |
| 10 mm and above | 10–12 × thickness | 10 mm plate → 100–120 mm V |
Air bending, bottoming and coining
This calculator is based on air bending, the most common method on modern CNC press brakes, because it is flexible, efficient and needs less tonnage than bottoming or coining.
Air bending
The punch pushes the material into the V-die without forcing it fully to the bottom. Bend angle is controlled mainly by punch depth, and tonnage is generally the lowest of the three methods.
Bottoming
Material is pressed further into the die so it follows the punch and die angle more closely. Can improve angle consistency but needs roughly 2–4× the air bending tonnage.
Coining
Very high force plastically compresses the material at the bend point, reducing springback. Needs roughly 5–10× (or more) the air bending tonnage — normally specialist applications only.
Press brake sizing FAQ
What size press brake do I need?
It depends on material type, thickness, bend length, V-die opening and the parts you're producing. Calculate the tonnage for your longest, thickest bend, then choose a machine with enough tonnage, bed length, throat depth, open height and stroke.
How is press brake tonnage calculated?
Tonnage is calculated from material tensile strength, thickness, bend length and V-die opening. Thicker material, longer bends and smaller V openings all increase the tonnage required.
What V-die opening should I use?
As a guide, 1–3 mm material typically uses around 6× the thickness, 4–8 mm uses around 8× the thickness, and 10 mm+ uses around 10–12× the thickness.
Does this calculator work for panel benders or folders?
No. It is designed for press brakes using air bending with an upper punch and lower V-die. Panel benders and folders bend the flange with a clamping beam and are sized differently — contact Plasquip for help with these.
Can Plasquip help me choose the right machine?
Yes. Send us your material type, thickness, bend length, drawings and production requirements and we can recommend a suitable press brake, tooling package, control system and backgauge.
Need help choosing a press brake?
Talk to an Australian machinery specialist on 1300 722 868.