CNC bending of CNC press brake is an important process of sheet metal processing. Sheet metal can be bent into various shapes after a few passes. Let’s take a look at the process of CNC bending.
CNC bending process:
1. The main types of bending knives are shown in picture below.
2. The main application bending types of various tools
(1) Straight knife: It is generally preferred to bend only one bend without considering avoiding position, as shown in picture below:
However, if the following situations occur, you need to consider avoiding positions, as shown in picture below:
It can be seen from Fig. 3 that the bending is obviously interfered. At this time, another type of bending knife should be considered for bending. In the situation on the left side of Figure 3, a small scimitar may be preferred to avoid position depending on the situation :
In the situation on the right side of Figure 3, a sharp knife should be used to avoid the position, but at the same time, it should be noted that because the tip of the sharp knife is very sharp, its strength is relatively poor, so it cannot be used for bending thick plates, generally 1.5mm The above plate thickness does not use sharp knives, but in the process arrangement, think of ways, such as arranging the pressure riveting nut process after bending, etc., as shown in picture below.
There are also such cases. When the small scimitar cannot avoid the position, the big scimitar should be used to avoid the position, as shown in picture below.
But sometimes a big scimitar cannot be avoided, so you need to increase the process: first press a mark on the bending line, as shown in picture below; for better bending, you can first bend this way to a certain extent Angle, avoid touching the knife, and then press the edge to 90 degrees, as shown in Figure 8. In general, the embossing process can be applied to the bending that cannot be completed at one time, so that the bending line can be better when the second bending is performed Forming according to the original bending print, otherwise it is easy to bend twice and cause the bending deviation, or the bending angle is not well controlled.
Therefore, such issues must be considered in the design process, and try to avoid using such a process when the requirements are met, because this does not have a good effect of direct bending, and there may be deviations in size and angle.
The bending machine can also be used to press the dead edge of the workpiece. First, the workpiece is bent to 30 degrees, and then the workpiece is crushed to death with a flat knife. Generally, the dead edge that can be completed with a normal punch is not arranged in the bending machine as much as possible, because the punch press The dead side effect is relatively better.
In addition to the interference between the workpiece and the bending knife during the bending process, when the size of the workpiece is relatively large, interference with the bending machine may also occur during bending.
When we arrange the process, we often have to consider whether it is easy to bend and whether it can be bent. Because bending is a very important process, whether the bending is good or not directly affects the guarantee of bending quality. The quality problems that occurred at that time all came from the bending size not being well controlled, so special attention should be paid to the bending problem during the design process, which is related to the stability of the product quality during mass production.
For different plate thicknesses, its bending size is limited and cannot be too small. Generally, it is related to the lower die. The general principle is: the lower die selects a groove 6 times the thickness of the plate, so the bending coefficient Most consistent with experience value. Generally, the classification of slats is divided according to the outer width of the slats as shown in Figure 9, which are No. 6 and No. 10 respectively.
However, when a small enough slot is used for bending, it is easy to have indentation. Generally, the indentation below the 6th slot is more obvious. Therefore, when the surface of the workpiece is not treated, when the bending edge is relatively small, there will be obvious indentation. First, it affects the appearance, and second, it is easy to rust, so pay attention to it when designing.
In the actual bending process, various problems will be encountered. In many cases, the impact of bending on other processes must be considered. In many cases, specific problems must be analyzed in detail and the process must be properly arranged.
At the same time, in some special needs, the supplier will also manufacture special bending knives, but if the shape of the tool is stranger or the curvature becomes larger, it will inevitably affect the rigidity of the tool and shorten the tool life.