The minimum bending edge here refers to the minimum edge that can be bent at once. Here we do not consider the strength of the mold, only discussing the relationship between the V-groove and the minimum bending edge.
Why does bending have a minimum bending edge? The reason is that during bending, if the edge is suspended, the bending will slip, and the bending will not achieve the desired dimensions. Therefore, studying the minimum bending edge is to address the issue of slipping during bending.
As shown in the figure below, the positioning scale of the minimum bending edge for a 1.0 thickness plate is illustrated. Calculating the minimum bending edge has an approximate empirical formula: L=V/2+1.8T+.5 (0.5 is the flange segment), and a more accurate formula is the ZTE bending formula: L=V/2+K/2+.5 (K is the external compensation amount), provided that the external compensation amount is known.
Through the figure below, we deepen our understanding of the minimum bending edge. The theoretical formula is:
L=V/2+K/2+X=V/2+K/2+tan(90-a)/2*R. When a=90, L=V/2+K/2+0.414*R. (X is the minimum flange). When R=1.2, the minimum flange amount is 0.5, so the empirical formula and the ZTE formula mentioned above are only suitable for situations with relatively small plate thicknesses (t<=3.0), and because the thickness of the sheet metal used for bending is also relatively small, the above formulas are quite universal.
In practical production, due to the different molds used by each company and the different wear on the R angle, the minimum bending edge varies. The larger the wear on the R angle, the larger the minimum bending edge. Below is the corresponding minimum bending edge for the corresponding V-groove and plate thickness (calculated using the empirical formula):
V-groove / Plate thickness
0.5 (4v) 3.0
0.8 (4v/5v) 3.2/3.7
1.0 (6v) 4.4
1.2 (6v/8v) 4.5/5.5
1.5 (8v/10v) 5.8/6.8
2.0 (12v) 8.3
2.5 (14v/16v) 9.7/10.7
3.0 (16v/18v) 11.1/12.1
4.0 (25v) 16.5
Note:
1. The minimum bending height includes one material thickness.
2. When the V-shaped bending is a sharp angle, the shortest bending edge needs to be increased by 0.5.
3. When the material of the part is aluminum or stainless steel, the minimum bending height may have slight variations, with aluminum being slightly smaller and stainless steel slightly larger.
