When the standard punch cannot avoid the position, the gooseneck punch should be selected to avoid the position, as shown in figure (1).
However, sometimes the gooseneck punch cannot avoid the position, so it is necessary to increase the process: first press a seal on the bending line – as shown in figure (2)
For better bending, this bending can be folded to a certain angle to avoid blade collision, and then press the edge to 90 degrees, as shown in figure (3)
In general, the embossing process can be applied to bending which can not be completed at one time.
In this way, during the second bending, the bending line can be better formed according to the original bending, otherwise it is easy to cause bending deviation or poor control of bending angle due to the second bending.
Therefore, such problems should also be considered in the design process.
If the requirements are met, try to avoid using such process, because it has no good effect of direct bending, and there may be deviation in size and angle.
The press brake can also be used to press the edge of the workpiece. First bend the workpiece to 30 degrees, and then press the workpiece with a flat punch. However, generally, the hemming edge completed by ordinary punch shall not be pressed by the press brake as far as possible, because the effect of hemming edge by the punch press is relatively better.
During the bending process, in addition to the interference between the workpiece and the bending knife, when the size of the workpiece is relatively large, it may also interfere with the press brake during bending.
When we arrange the process, we often have to consider whether it’s easy to bend and whether it can be bent.
Because bending is a very important process, the good operation of bending directly affects the guarantee of bending quality, and many quality problems are caused by the poor control of bending size.
Therefore, special attention should be paid to the bending problem in the design process, which is related to the stability of product quality during mass production.
For different plate thickness, its bending size is limited and can not be too small. Generally, it is related to the lower die.
The general principle is: select the V opening with 6 times the plate thickness for the lower die, so that the bending coefficient is most consistent with the empirical value.
The general die slots are classified according to the outer width of the slot, as shown in figure (4), which are #6 and #10 slots respectively.
However, when a small enough groove is selected for bending, indentation is easy to occur. Generally, the indentation below #6 groove is obvious.
Therefore, when the workpiece surface is not treated, and the bending edge is relatively small, there is obvious indentation.
On the one hand, it affects the appearance, and on the other hand, it is easy to rust, so we should pay attention to it in design.
As can be seen from the figure above, for slot #10, the distance from the bending line to the positioning edge must be greater than 5.0mm before bending.
It can be seen that generally, #4 slot is the smallest tool slot, and the distance from the bending line to the positioning edge should be greater than 2.0mm.
Generally, #4 slot is mostly used for thin plate (less than 1.2mm).
Because if the thick plate is bent, the pressure required is relatively large and the groove is small, it is easy to burst the knife groove.
Therefore, for bending 1.0mm plate, it is better if the bending edge is greater than 3.5mm (there will be indentation);
For bending 1.5mm plate, the bending edge shall be greater than 5.0mm.
The bending edge of 3.0mm plate shall be greater than 12mm.
Such problems can be considered in the design process.
Various problems will be encountered in the actual bending process.
In many cases, the impact of bending on other processes should be considered and specific problems should be analyzed and the process should be arranged appropriately.
At the same time, under some special needs, the supplier will also manufacture special bending tools.
However, if the shape of the tools is more strange or the curvature is greater, it will inevitably affect the rigidity of the cutter and reduce the service life of the blade.