CNC steel pipe bending machine also has a certain requirement for the length when bending pipes.The linear section is too short, then the fixture length design also should be short, clamping part force is not enough, can not be clamped, so it needs to improve the length. So how long does it take to bend properly?

Figure 1  Length of straight section of bending

According to design experience, the clamping strength can be guaranteed only when the length is more than three times of the pipe diameter. If the clamping distance is not enough and the clamping area is too small, the clamping die is too small to press the pipe when the pipe is bent, and the bending deformation of the pipe is easy to occur, or the pipe can not be clamped due to the insufficient clamping force, and the pipe will rebound during bending, causing the bending Angle is not in place. So is it necessary to set three times of the pipe diameter? In fact, short length is not impossible to bend. It is necessary to reform the feeding car motor of CNC pipe bender to increase the power. When the head of the machine enters to bend, the feeding car will push forward with the speed of the bend, so that the rebound force of the pipe fitting during bending can be shared by the auxiliary push of the feeding car. If the distance is shorter, the forming die is needed to ensure the holding area (Figure 2).

Figure 2  Forming Die