Preparing your drawings for bending
To get started effectively, learn more about the required drawings for bending, the file types we accept along with any bending specifications. Furthermore, explore the intricacies of metal bending and the detailed information we require to successfully bring your project to life.
Boxes – Clearances
Before manufacturing begins, when producing a box or an item where two adjacent flanges intersect at a corner, the tolerances, desired clearances between them and their bending sequence must be carefully considered.
During the design phase
Producing a box or an item where two adjacent flanges intersect at a corner requires careful consideration of tolerances, desired clearances, and bending sequence in your drawings for bending. We recommend a minimum clearance of 0.2mm to account for any variation in material thickness, as well as linear and angular tolerances.
When bending items with offset flanges, the bending sequence plays a crucial role in achieving precision. Our technicians deliberately bend the workpiece beyond the desired angle during the forming process to ensure it forms correctly after spring back, once pressure from the tooling is released. This is why accurate drawings for bending are essential to the success of our process.
Ensuring the flanges are bent in the correct sequence avoids collisions with tooling or other flanges.
Boxes – Clearances
When producing a box or an item where two adjacent flanges intersect at a corner, the tolerances, desired clearances between them and their bending sequence must be considered.
Before manufacturing begins, producing a box or an item where two adjacent flanges intersect at a corner requires careful consideration of tolerances, desired clearances, and bending sequence. Furthermore, our engineering team thoroughly analyses these critical factors to ensure a precise fit and structural integrity in the final component.
Step Bending
Step bending is also known as bump forming.
If the required internal radius exceeds what can be achieved with a single bend, step bending becomes necessary. Our machines allow parts that would typically be rolled to instead be bent repeatedly to achieve the desired shape.
Images below show parts designed for rollers alongside those adapted for step bending on press brakes. We can create an almost exact match between the two. Consistent flange lengths are essential in producing step bends, as they ensure a more refined and uniform appearance.
Flange length depends on the material and thickness of the part. For instance, a part made from 3mm mild steel requires a minimum flange length of 13mm. This requirement also applies to the final flange, which must rest securely on the die in the press brake.
Bend Spacing Distaces
If the required internal radius exceeds what can be achieved with a single bend, step bending becomes necessary. Our machines allow parts that would typically be rolled to instead be bent repeatedly to achieve the desired shape.
Images below show parts designed for rollers alongside those adapted for step bending on press brakes. We can create an almost exact match between the two. Consistent flange lengths are essential in producing step bends, as they ensure a more refined and uniform appearance.
Flange length depends on the material and thickness of the part. For instance, a part made from 3mm mild steel requires a minimum flange length of 13mm. This requirement also applies to the final flange, which must rest securely on the die in the press brake.
Bend Spacing Considerations
The distance between each bend is determined by the material’s thickness and type. Materials that are thicker and more rigid, or have higher tensile strength, require greater pressure to bend. In order to apply enough pressure while staying within the press brake’s tonnage limits, tooling with wider grooves is necessary. This means that thicker, more rigid materials cannot accommodate smaller distances between bends. As a result, unbent flanges beyond the bend’s endpoint are unavoidable.
Bend Spacing Considerations
Distance between each bend is determined by the material’s thickness and type. Thicker and more rigid or less flexible materials (such as those with higher tensile strength) require greater pressure to bend. In order to apply sufficient pressure while staying within the press brake’s tonnage limits, tooling with wider grooves becomes essential. As a result, thicker and more rigid materials cannot accommodate smaller distances between bends.
Unbent flanges beyond the bend’s endpoint are inevitable. To form bends without distortion, the punch must descend onto the workpiece, ensuring it remains in contact with the top edge of the die (bottom tooling) without slipping into the tool. Consequently, an area on either side of the bend remains unformed.
Flange Lengths
We have specified minimum flange lengths based on the thickness and material of each part. These requirements are essential to ensure that all bent components are fabricated to the highest quality standards, thereby preventing any risk of deformation.
The minimum flange length is determined by the die length. When material thickness increases, so too does the die size. As a result, the thicker the part, the larger the required flange length.
For further clarity, view all of our material flange lengths in relation to material thicknesses below.
| THICKNESS – MILD STEEL | MINIMUM FLANGE LENGTH |
|---|---|
| 0.7, 0.9, 1.2 | 8 |
| 1.5, 2 | 9 |
| 2.5 | 11 |
| 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 | 8 |
| 1.2, 1.5 | 9 |
| 2 | 11 |
| 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 | 8 |
| 2 | 9 |
| 2.5 | 11 |
| 3 | 14 |
| 4 | 17 |
| 5, 6 | 25 |
| THICKNESS –COPPER | MINIMUM FLANGE LENGTH |
|---|---|
| 0.9, 1.2 | 8 |
| 1.5, 2 | 9 |
| 2.5 | 11 |
| 3 | 14 |
| 4 | 20 |
| 5 | 25 |
| THICKNESS –BRASS | MINIMUM FLANGE LENGTH |
|---|---|
| 0.9, 1.2 | 8 |
| 1.5, 2 | 9 |
| 2.5 | 11 |
| 3 | 14 |
| 4 | 20 |
| 5 | 25 |
Flange Lengths
We have specified minimum flange lengths based on the thickness and material of each part. These requirements are essential to ensure that all bent components are fabricated to the highest quality standards, thereby preventing any risk of deformation.
The minimum flange length is determined by the die length. When material thickness increases, so too does the die size. As a result, the thicker the part, the larger the required flange length.
For further clarity, view all of our material flange lengths in relation to material thicknesses below.
| THICKNESS – MILD STEEL | MINIMUM FLANGE LENGTH |
|---|---|
| 0.7, 0.9, 1.2 | 8 |
| 1.5, 2 | 9 |
| 2.5 | 11 |
| 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 | 8 |
| 1.2, 1.5 | 9 |
| 2 | 11 |
| 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 | 8 |
| 2 | 9 |
| 2.5 | 11 |
| 3 | 14 |
| 4 | 17 |
| 5, 6 | 25 |
| THICKNESS –COPPER | MINIMUM FLANGE LENGTH |
|---|---|
| 0.9, 1.2 | 8 |
| 1.5, 2 | 9 |
| 2.5 | 11 |
| 3 | 14 |
| 4 | 20 |
| 5 | 25 |
| THICKNESS –BRASS | MINIMUM FLANGE LENGTH |
|---|---|
| 0.9, 1.2 | 8 |
| 1.5, 2 | 9 |
| 2.5 | 11 |
| 3 | 14 |
| 4 | 20 |
| 5 | 25 |
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.
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 the internal radii we can achieve per thickness for each material. While different grades and types of material, such as Galv, Zintec, S355, and 316, may cause slight variations in the radii, these variations are typically 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 |
Internal radiuses
The chart indicates the internal radii we can achieve per thickness for each material. While different grades and types of material, such as Galv, Zintec, S355, and 316, may cause slight variations in the radii, these variations are typically 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 are often at risk of deformation, as they may fall into the fold, altering their shape and size. Additionally, the hole could catch on the die, leading to tearing and potential damage to the part. To prevent this, holes near the bend zone can be added as a secondary operation after bending, unless distortion is intentional.
There are limited options for fixing warped holes. Some parts may be compatible with supportive dies for a smaller internal radius; however, this may not meet specific radius or angle requirements. During the quoting process, we will carefully assess compatibility with alternative dies to ensure the best possible outcome.
Holes In The Bend Zone
Holes near the bend zone are often at risk of deformation, as they may fall into the fold, altering their shape and size. Additionally, the hole could catch on the die, leading to tearing and potential damage to the part. To prevent this, holes near the bend zone can be added as a secondary operation after bending, unless distortion is intentional.
There are limited options for fixing warped holes. Some parts may be compatible with supportive dies for a smaller internal radius; however, this may not meet specific radius or angle requirements. During the quoting process, we will carefully assess compatibility with alternative dies to ensure the best possible outcome.
