Bend Relief Sizer

Design for Manufacturability (DFM): Calculate the minimum relief width and depth required to prevent material tearing at the edges of a bend.

Recommended Relief Size
Relief Width (W)
0.000
in

Standard (1.5 × T)

Relief Depth (D)
0.000
in

Minimum (R + T)

Absolute Minimum Width: 0.000 in (1.0 × T)
Visual Geometry
W D BEND LINE
Why use reliefs?

When a bend is made, the material near the bend line is subjected to high stress. If the bend is too close to a straight edge, the material will "pull" and tear. A relief cut provides a controlled gap that allows the material to deform without damaging the surrounding geometry.

Design Rules
  • Width (W): Should be at least equal to the material thickness ($T$), but $1.5 \times T$ is preferred for laser or waterjet cutting.
  • Depth (D): Must extend at least to the end of the bend radius. The common formula is $Radius + Thickness$.
  • Shape: Round reliefs (obround) are better for stress distribution, while square reliefs are easier to machine on manual equipment.
Pro Tip: Most modern CAD software (SolidWorks, Inventor) applies these rules automatically, but manual verification ensures your part won't fail in the press brake.