1. Minimum bending radius of plate
When the plate is bent, if the fillet of the bend is too small, cracks are likely to form on the outer surface. If the bend fillet is too large, the accuracy of the bent part is difficult to guarantee due to the influence of springback, as shown in the figure below. For this reason, the minimum bending radius is specified. See Table 4.1-3.
2. The height of the straight edge of the bend should not be too small, otherwise it is difficult to form a sufficient bending moment and it is difficult to obtain parts with accurate shapes. The value h≥R+2t is acceptable. See the figure below.
3. When punching the bent edge, the distance L from the hole edge to the center of the bending radius R must not be too small to avoid deformation of the hole after bending. The value L≥2t is acceptable. See the figure below.
4. When a＜R, after bending, there is still a residual arc on the b side near a. In order to avoid the residual arc, a≥R must be required. See the figure below.
5. On U-shaped bent parts, the two bending edges should preferably be of equal length to avoid displacement to one side during bending. If not allowed, a process positioning hole can be set. As shown in the figure below.
6. Prevent cracks or deformities when the side (trapezoidal) is bent. A reserved cut should be designed, or the root should be changed to a stepped shape. The groove width K≥2t, the groove depth L≥t+R+K/2. As shown in the figure below.
7. To prevent the rounded corners from wrinkling after being squeezed and squeezed during bending, a reserved cut should be designed. For example, the cut form at the rounded corner of the side panel (upper and lower ends) of the outdoor unit is shown in the figure below.
8. To prevent wrinkles on the two sides of the right angle after bending, a reserved cut should be designed. See the figure below.
9. The cut form to prevent rebound after bending. See the figure below.
10. The cut form to prevent cracks after punching. See the figure below.
11. Prevent one side from shrinking inward when bending. You can design process positioning holes, or bend both sides at the same time, and you can also solve the shrinkage problem by increasing the width. See the figure below.
12. Overlapping form with right angles. See the figure below.
13. Bending of convex parts
If the bending line and the step line are consistent as in Figure a, sometimes cracks and deformations will occur at the root. Therefore, make the bending line leave the step line as shown in Figure b, or design the incision as shown in c and d. See the figure below.
14. To prevent the hole on the bending surface from deforming after being stressed during bending, the hole margin (to the bottom root) must be A≥4.
