Radius < R30
If the bending radius of the arc workpieces are smaller than R30, generally it can be bent directly with a circular plate bending mold (as shown in Figure 1).
When the upper mold is fixed, it is recommended to use the upper mold fixing method as shown in the figure which makes it convenient to disassemble.
When adding new molds, it will also be helpful to reduce costs.
The products produced by this process have high precision and accurate size, and are suitable for large-scale precision sheet metal parts.
Generally, for the arc workpiece with the radius smaller than R30, and the requirement for the size tolerance of the work is not high, one round tube with a diameter equal to the arc of the sheet metal part can be directly placed on the surface of the metal plate. The lower die directly uses a V-groove with a width larger than the diameter of the arc. (as shown in figure 2)
Use a common bending upper die tip to press the round pipe and apply it to the sheet metal to achieve the purpose of forming.
Radius > R30
Generally, for an arc sheet metal with radius larger than R30, the arc of the segment can be unfolded, and according to the size to calculate how many bending times is required to bend form shape, so that the positioning size of each bending can be calculated.
Then calculate the angle of each bend according to the relationship between the total arc angle and the total number of bends.
When making sheet metal parts by this process, for the same arc size, the more the number of bends, the better the effect and the smoother the surface.
When bending such products, the starting point of the bender ram stroke can be adjusted to increase the bending speed.
The completed workpiece is shown in the following figure:
For more information about how to achieve large radius in sheet metal parts, you can read the article about bump bending.