How to adjust the bending radius and bending degree of pipe bender

When bending with a free pipe bender, the bending radius of the pipe bender is 0.156 times of the opening distance of the female die. In the bending process of free pipe bender, the opening distance of female die shall be 8 times of the thickness of metal material. For example, when a 1 / 2 inch (0.0127m) opening is used to form 16 gauge mild steel, the bending radius of the pipe bender of the part is about 0.078 inch. If the bending radius of the pipe bender is almost as small as the material thickness, it must be formed with a bottom concave die. However, the pressure required for the forming of bottomed die is about 4 times greater than that of free bending machine. If the bending radius of the pipe bender is less than the material thickness, the punch with the front fillet radius less than the material thickness must be used, and the bending method of the embossed pipe bender shall be resorted to. In this way, 10 times the bending pressure of the free pipe bender is required. For the bending of free pipe bender, the punch and die shall be processed according to 85 ° or less (small points are better). When using this group of dies, pay attention to the gap between the punch and the die at the bottom of the stroke and the excessive bending of the pipe bender that is sufficient to compensate for the rebound and keep the material at about 90 °. Generally, the springback angle generated by the bending die of the free pipe bender on the new pipe bender is ≤ 2 °, and the bending radius of the pipe bender is equal to 0.156 times of the opening distance of the female die. For the bending of the pipe bender with bottom die, the die angle is generally 86 ~ 90 °. At the bottom of the stroke, there should be a gap slightly greater than the material thickness between the male and female dies. The forming angle can be improved because the bending tonnage of the pipe bender with bottom die is large (about 4 times that of the free pipe bender), which reduces the stress that usually causes rebound within the bending radius of the pipe bender. The bending of embossed pipe bender is the same as that of the pipe bender with bottom die, except that the front end of the punch is processed into the required bending radius of the pipe bender, and the gap between the punch and die at the bottom of the stroke is less than the material thickness. The springback is basically avoided by applying enough pressure (about 10 times that of the free bending machine) to force the front end of the punch to contact the material. In order to select the low tonnage specification, the bending radius of the pipe bender greater than the material thickness shall be planned, and the free pipe bender bending method shall be adopted as far as possible. When the bending radius of the pipe bender is large, it often does not affect the quality of the finished parts and their future use.
The bending accuracy requirement of pipe bender is a factor that needs careful consideration. It is this factor that determines whether a CNC pipe bender or a manual pipe bender needs to be considered. If the bending accuracy of the pipe bender is required to be ± 1 ° and cannot be changed, we must focus on the CNC machine. The repeated accuracy of the slide block of CNC pipe bender is ± 0.0004 inch. Such accuracy and good die must be adopted for the accurate angle of forming. Generally, the deviation of ± 0.002 inch will be produced by using the manual control die under the condition of suitable bending machine repetition. In addition, the CNC pipe bender is ready for rapid die installation, which is an indisputable consideration when many small batch parts need to be bent.