What is springback in press brake bending?
Springback is the elastic recovery of the material when the punch is withdrawn. Part of the section was only elastically stressed, so it returns towards its original shape, the bend opens by a few degrees and the radius grows slightly.
Why does the radius-to-thickness ratio matter so much?
Springback grows as the R/t ratio increases, because a larger radius means a smaller proportion of the material thickness is deformed past its elastic limit. A tight bend in thin material is almost all plastic; a generous radius is largely elastic recovery.
| R/t ratio | Indicative springback | Practical comment |
|---|---|---|
| Below 1 | 2–4 % | Little correction needed |
| 1 to 3 | 3–6 % | Normal air bending range |
| 3 to 6 | 5–9 % | Correction needed for a held angle |
| Above 6 | 8–15 % | Large-radius work; expect to overbend |
How do I measure springback on my own material?
Bend a trial part to a known programmed angle, measure the angle after the load is released, and record the difference. Repeat at the radius and material you will run, because published factors are only a starting point.
- Program a known angle, for example 90 degrees, on the production material.
- Bend and remove the part, then measure the finished angle with a protractor or angle gauge.
- The difference is the springback at that radius and thickness.
- Scale it for other angles on the same material and tooling as a first estimate.
How is springback compensated in production?
Overbend and let the material relax back, use an adjustable or movable-bottom die, or use a CNC press brake with angle measurement and depth correction. Heavy loading such as coining reduces the recovery but needs dedicated tooling and much higher force.
| Method | Correction quality | Note |
|---|---|---|
| Overbend programmed angle | Good for a single angle | Simple, needs a trial part |
| Adjustable die | Continuous | Suits variable radius and angle |
| CNC angle correction | Best for repeat work | Requires a measured first part |
| Coining | Recovery largely removed | High force, job-specific tooling |
Does the die opening affect springback?
Yes, indirectly. A wider opening produces a larger inside radius for the same thickness, which raises R/t and therefore raises springback. Changing the die is therefore also changing the correction you need.
Is springback larger in stainless or high-strength steel?
Yes. Higher yield strength and more work hardening mean more elastic recovery, so stainless steel and high-strength steels need noticeably more overbend than mild steel at the same R/t.
Related technical pages
Springback calculator
Estimate the overbend angle from the material and R/t.
Bend allowance guide
Correct the flat pattern for the final radius and angle.
Radius dies
Dies for large-radius bends, where springback is greatest.
Tooling setup guide
Setting and aligning tooling so the first part is close.
Next step
Tell us the material grade, thickness and the angle tolerance and we will recommend tooling and a starting correction.
Request a quotation