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Sheet Metal Bending and Forming Guidelines

Sep 24, 2022 | Design Guide

In the bending process, the shape is created through plastic deformation in the bending position using the bending die under a hydraulic press. We can maintain a tolerance of ± 0.25 mm in length and ±1 degree in bending angle. It will be more accurate if you consider the following critical guidelines regarding Sheet Metal Bending and Forming.

1. K-factor

K-factor is an essential parameter while creating the bending design, which is the ratio of the distance of the neutral axis to the sheet thickness. You must input the correct k-factor value in CAD software (0.25 to 0.5).

2. Uniform Wall thickness

Maintaining uniformity of wall thickness in design is another critical aspect of precise production. You must keep the wall thickness consistent throughout the design. ProleanHub can provide bending of sheet metal thickness up to 10 mm with Single sheet punching. If you have doable countersinks with counter-bores in design, that will need post-machining.

3. Bending radius

Keeping the Bending position in the same pale and direction is crucial. If the orientation needs to change, that will cost money and time. In addition, if the bending radius is consistent, that will also make the fabrication process more straightforward. Furthermore, the minimum inner bend radius cannot be less than the thickness of the sheet.

4. Distance between hole & bending position

The bending position should maintain a minimum distance from the hole. If there is insufficient space, the material will distort on the hole side during the bending process. Use the bending force chart to keep the bending position slightly more than the minimum allowable distance.

The general rule of practice is that the hole should be at least 2.5 times the sheet thickness plus the bend radius away from the bending position, and the slots should be at least four times the sheet thickness plus the bend radius away from the bending part.

5. C-channel & U-channel

Do you have a C-channel & U-channel on the design? If you have, the length of each flange needed to be created should not be more than half of the base. For example, if the base is 4″ then the flange at either side can have a maximum of 2″ length.

6. Fillets

The design might have sharp corners, which can cause injuries while operating and even affect the functionality of the parts. So, consider the fillets on the corners. Designing fillets with half of the sheet thickness is an excellent choice.

You might leave a tiny radius within the hem to strengthen the edges. A practice called hemming. It also reduces the possibility of cracking.

7. Notch & Tabs

The size of the notches cannot be less than the thickness of the sheet or greater than five times the thickness. At the same time, tabs must be at least twice the thickness and no more than five times the width.

NotchThe thickness of the sheet5 x thickness
Tabs2 x thickness5 x width



  • The format of the file is according to the format we accept
  • There is no text in your design. If any, they are in vector values as anchor points and curves.
  • No intersecting or over-lapping lines in the design
  • Designed are scaled as 1:1
  • There are no void objects or open contours in the file.

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