Sheet metal bending — how to design parts for the press brake
Bending adds a third dimension to flat parts, but it requires the right design. We cover minimum flanges, bend radii, bend relief, and how to account for the flat pattern.
Laser cutting produces a flat part, but many components need a third dimension. That dimension is added by bending on a press brake. For the result to fit precisely, the part must be designed with the bending process in mind already at the drawing stage.
Minimum flange length
The flange (the bent portion) must not be too short — the press brake tooling needs material to hold. A practical minimum is roughly four times the sheet thickness plus the bend radius. For 2 mm sheet, plan for a flange of at least 10–12 mm.
Bend radius
A sharp 90° bend with a zero radius does not exist — every bend has an inside radius. As a starting rule, the inside radius should be at least equal to the material thickness. Too small a radius leads to cracking, especially with harder materials.
Bend relief
If a bend ends at the edge of a part, the material can tear or deform. The solution is a bend relief — a small notch at the end of the bend line that releases the stress. It is good practice to prepare this detail directly in the DXF.
Flat pattern and elongation
During bending, the material stretches on the outside and compresses on the inside. The total flange length is therefore not a simple sum of dimensions — you must account for the bend deduction. Just supply a 3D model or exact dimensions and we will calculate the flat pattern for you.
Holes near a bend
Holes placed too close to the bend line deform into ovals during bending. Keep them at least 2.5 times the thickness plus the radius away from the bend. If that is not possible, design the hole outside the bend zone.
Conclusion
A well-designed bent part is made in one setup, precisely and without rework. If you are unsure about flange, radius, or flat pattern, send us your drawing — we will help prepare it for production.
