Compare preliminary forming-force requirements for air bending and bottoming using material, thickness, bend length and die opening.
| Method | Base Force | Multiplier | Setup Factor | Estimated Force | Relative Force |
|---|
A commonly used preliminary air-bending tonnage relationship can be expressed using material thickness, bend length, tensile strength and V-die opening.
Where F is forming force, Rm is tensile strength, L is bend length, t is material thickness and V is the die opening. The coefficient and unit conversion depend on the calculation convention used.
Bottoming requires the sheet to be pressed substantially into the die geometry. As a result, the required force can be considerably higher than air bending.
This calculator uses a configurable preliminary multiplier rather than presenting a universal fixed factor because actual bottoming force depends strongly on tooling, material and machine conditions.
Material tensile strength has a direct influence on preliminary forming-force calculations. Stronger materials generally require greater force for the same thickness, bend length and die opening.
The material selector provides typical reference strengths, but the entered tensile strength is used for the calculation.
For air bending, a larger V-die opening generally reduces the calculated forming force because the force relationship includes the die opening in the denominator.
Changing the die opening can therefore significantly change the estimated machine requirement.
What does this calculator compare?
It compares preliminary forming-force requirements for air bending and bottoming using the same material, thickness, bend length and die opening.
Why does bottoming require more force?
Bottoming forces the material more completely into the die profile, producing substantially higher forming loads than typical air bending.
Does a wider die opening reduce air-bending force?
Generally, yes. Common air-bending force relationships include V-die opening in the denominator.
Does material strength affect force?
Yes. Higher tensile strength generally increases the required forming force for the same geometry.
Can I use this to select a press brake?
It can provide preliminary force estimates, but machine selection should use the manufacturer's rated tonnage, tooling limits and approved force charts.
Are the bottoming force results exact?
No. Bottoming force is particularly dependent on the actual tooling, material and machine setup, so the result should be treated as a screening estimate.