When many customers give us the sample drawings, there will be a problem, that is, the large steel pipe bending radius of the pipe fittings is very small, and there is no problem from the sample drawings. However, when applied to the mold, it will be found that it has a great influence on the structure of the mold. So what is the bend radius? It's actually the radius. This means that the center is high. As shown in Figure 1:

Figure 1:  Bending  Radius

The R in the figure is the square pipe bending radius we need when bending. The value of R can be large, but it cannot be too small. If it is too small, the die strength will not be able to support the bending force of the pipe. Figure 2 shows the shape of the wheel die. The relationship between the values A and R in the figure is shown in Table 1.

Figure 2: Bending die structure

Table 1: Influence of Bending Radius on Bending Die

It can be seen from Table 1 that the smaller the ratio of R to D, the smaller the A value. The value of A affects the strength of the wheel die. The smaller A is, the smaller the force strength of the wheel die is, and it is likely to break during bending, and the mounting shaft of the wheel die itself needs to be punched in the center. According to the summary of practice, it is the best value for the elbow to be greater than 1.5D, and the strength of the wheel die above this value can meet the requirements. Therefore, when the general customer's value is not in line with the design, we will ask the customer to design according to this value as much as possible.