The metal bending process
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Let’s get technical and explore the intricacies of metal bending and the information we require to bring your project to life.
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File types we accept
Our extensive list of file types we can accept for bending.
| 3D File Import | Extension(s) | Version(s) |
|---|---|---|
| Acis | .sat | R1 to 2023 1.0 |
| Catia V4 | .model .exp | 4.1.9 to 4.2.4 |
| Catia V5 | .CATPart .CATProduct | V5R8 to V5-6 R2023 |
| 3DExperience | .CATPart .CATProduct | Up to V6 R2023x * |
| ProE / Creo | .prt .asm | 16 to Creo 9.0 |
| IGES | .igs .iges | Up to 5.3 |
| Inventor | .ipt .iam | V6 to V2023 |
| JT | .jt | 8.x 9.x 10 10.2/3/5/6/7 |
| Parasolid | .x_t .xml_txt | 9 to 35.0.X |
| Siemens NX | .prt | NX 1 to NX 2212 |
| Solid Edge | .par .asm .psm | V18 to SE2023 |
| Solidworks | .sldprt .sldasm | 2003 to 2023 |
| STEP | .stp .step | 203, 214, 242 |
| DWG / DXF | .dwg .dxf | all |
Bend Reliefs
Using bend reliefs is crucial in metal bending. Without them, metal is at risk of tearing and deforming. Bend reliefs enable controlled bending, resulting in a clean finish.
The images below show how including or omitting bend reliefs impacts the forming process. Without them, deformation risks increase, and flanges may pull on adjacent, non-bent areas, leading to tearing.
In contrast, adding bend reliefs ensures easy, clean bends by preventing distortion. These small cutouts, typically matching the bend radius, are placed around the bend zone to facilitate smoother bending and avoid unintended distortions.
Internal radiuses
The chart indicates what internal rads we can achieve per thickness for each material. Different grades / types of material such as Galv, Zintec, S355, 316 will mean the rads will vary slightly but are likely to vary no more than +/-1mm.
| MILD STEEL CR4 | MILD STEEL S275 | STAINLESS STEEL – 3042B | ALUMINIUM – 5251 | BRASS | COPPER | |
|---|---|---|---|---|---|---|
| 0.5 | 1.5 | 1 | ||||
| 0.7 | 1 | 1.5 | 1 | |||
| 0.9 | 1 , 1.5 , 2 | 1.5 , 2 , 2.5 | 1 | 1 , 1.25 , 1.5 | 1 | |
| 1.2 | 1 , 1.5 , 2 , 2.5 | 2 , 2.5 , 3.5 | 1 | 1 , 1.25 , 1.5 | 1 | |
| 1.5 | 1.5 , 2 , 2.5 , 3 | 2 , 2.5 , 3.5 , 4 | 1 , 1.25 | 1.25 , 1.5 , 2.25 | 1 , 1.5 | |
| 2 | 1.5 , 2 , 2.5 , 3 , 4 | 2.5 , 3.5 , 4 , 4.5 | 1 , 1.25 , 1.5 , 1.75 | 1.25 , 1.5 , 2.25 , 2.75 , 3 | 1 , 1.5 , 1.75 , 2 | |
| 2.5 | 2 , 2.5 , 3 , 4 , 5 | 3.5 , 4 , 4.5 , 5.5 | 1 , 1.25 , 1.5 , 1.75 , 2 | 1.5 , 2.25 , 2.75 , 3 , 3.5 | 1 , 1.5 , 1.75 , 2 , 2.5 | |
| 3 | 2.5 , 3 , 4 , 5 , 5.5 | 2.5 , 3 , 4 , 5 , 5.5 | 3.5 , 4 , 4.5 , 5.5 , 7.5 | 1.25 , 1.5 , 1.75 , 2 , 2.5 | 2.25 , 2.75 , 3 , 3.5 , 4.5 | 1.5 , 1.75 , 2 , 2.5 , 3 |
| 4 | 4 , 5 , 5.5 , 6 | 5.5 , 7.5 , 9.5 | 1.5 , 1.75 , 2 , 2.5 , 3.5 | 3 , 3.5 , 4.5 , 6 | 1.75 , 2 , 2.5 , 3 , 3.5 | |
| 5 | 5 , 5.5 , 6 , 12 | 5.5 , 7.5 , 9.5 , 15 | 2 , 2.5 , 3.5 , 5.5 | 3.5 , 4.5 , 6 , 10 | 2 , 2.5 , 3 , 3.5 , 5.5 | |
| 6 | 5.5 , 6 , 12 | 7.5 , 9.5 , 15 | 2 , 2.5 , 3.5 , 5.5 | |||
| 8 | 6 , 12 , 15 | 15 , 17 | ||||
| 10 | 12 , 15 | |||||
| 12 | 15 |
Holes In The Bend Zone
Holes near the bend zone often risk deformation as they may fall into the fold, altering their shape and size. The hole could also catch on the die, causing tearing and damaging the part. To avoid this, holes near the bend zone can be added as a secondary operation after bending, unless distortion is intended.
Limited options exist to fix warped holes. Some parts may work on supportive dies for a smaller internal radius, but this may not suit specific radius or angle requirements. During quoting, we’ll assess compatibility with alternative dies to ensure the best outcome.
Flange Lengths
We have specified minimum flange lengths based on the thickness and material of the parts. These requirements ensure that all bent components are fabricated to the highest quality standards and have no risk of deformation.
The minimum flange length is determined by the die length. As material thickness increases, the die size also grows. Consequently, the thicker the part, the larger the required flange length
View all of our material flange lenghts in relation to material thicknesses below.
| THICKNESS – MILD STEEL | MINIMUM FLANGE LENGTH |
|---|---|
| 0.7, 0.9, 1.2 | 7 |
| 1.5, 2 | 8 |
| 2.5 | 10 |
| 3 | 14 |
| 4 | 20 |
| 5 | 25 |
| 6 | 30 |
| 8 | 40 |
| 10 | 60 |
| 12 | 75 |
| THICKNESS – STAINLESS STEEL | MINIMUM FLANGE LENGTH |
|---|---|
| 0.5, 0.7, 0.9 | 7 |
| 1.2, 1.5 | 8 |
| 2 | 10 |
| 2.5 | 14 |
| 3 | 20 |
| 4 | 25 |
| 6 | 30 |
| 8 | 40 |
| THICKNESS – ALUMINUM | MINIMUM FLANGE LENGTH |
|---|---|
| 0.5, 0.7, 0.9, 1.2, 1.5 | 7 |
| 2 | 8 |
| 2.5 | 10 |
| 3 | 14 |
| 4 | 16 |
| 5, 6 | 25 |
| THICKNESS –COPPER | MINIMUM FLANGE LENGTH |
|---|---|
| 0.9, 1.2 | 7 |
| 1.5, 2 | 8 |
| 2.5 | 10 |
| 3 | 14 |
| 4 | 20 |
| 5 | 25 |
| THICKNESS –BRASS | MINIMUM FLANGE LENGTH |
|---|---|
| 0.9, 1.2 | 7 |
| 1.5, 2 | 8 |
| 2.5 | 10 |
| 3 | 14 |
| 4 | 20 |
| 5 | 25 |
TOLERANCES
Our bending tolerances include a range of ±0.25 mm for flange lengths, ±0.5 mm for the inner radius, and ±1° for the bend angle. When the material thickness is around 8 mm or thereabouts, this may result in the tolerance becoming larger. This is because thicker materials tend to experience more stretching, which can lead to greater variation in the final dimensions.
