Arc bending processing of sheet metal: arc processing can be divided into ordinary tool processing or arc tool processing (radius punch and rounding punch).
1. Bending arc with standard punch
Select 0.2R ordinary punch and die according to the die selection standard, calculate the arc length, and calculate the number of bends to complete the arc according to the arc length and material thickness, then calculate the bending angle of each bend according to the arc angle and the number of bends, and then perform the bending.
However, because the arc bending process is completed by bending several or even dozens of times, the size range of the bending arc is limited by the toolings.
General processing scope:
1) 90 degree circular arc: forming circular arc larger than R12;
2) Circular arc above 120 degrees: it can process all R circular arcs that are greater than the tool limit.
2. Bend arc with radius punch
The selection of the tool depends on the processing method.
For example, the selection of the V-groove width depends on the bending depth.
Related reading: Press Brake Bending Depth Calculator
The circular arc R angle is formed according to the inherent R angle of the tool.
When selecting the die, if the forming is less than R12 radius, the upper and lower dies with processing specifications can be selected for one-time forming.
Since R punch is a standard mold, the size of the R specification is limited, so the size of the processing arc specification is limited.
If the processing R is not within the standard mold specification, the R can be increased by adding materials around the R mold.
If the forming is greater than the R12 arc, it also needs to be formed by several bends, and the processing conditions are the same as those of arc bending with the standard punch.
Arc bending with radius punch has one advantage, which just makes up for the shortcomings of arc bending with standard punch.
The bending appearance is smooth and the effect is good. It can process products with strict appearance requirements.
3. Processing precautions
1) When bending arc with radius punch, first pay attention to the mold selection according to the mold selection standard.
However, when processing a 90 degree arc, due to the rebound of the sheet metal parts, when the lower die is processed at 90 degrees, the 90 degree arc cannot meet the requirements, so it needs to be pushed manually during bending to ensure the angle.
Therefore, under the premise of 88 degree lower die, 88 degree lower die should be preferred when processing 90 degree circular arc.
2) When processing the arc, it is required to use the detection fixture to detect, so as to ensure the processing appearance size
3) When processing the process angle arc, it is generally processed with an exchangable die or manually.
4) Select the width standard of the lower die V groove by using the R die (round bar and arc punch) to fold the arc.
- The width of V groove of lower die selected for bending 90 degree arc is: V>2 (R+T);
- The width of V groove of lower die selected for bending 135 degree arc is: V>1.5 (R+T).