In the design and arrangement of pipe bender, excessive arc, arbitrary curve, compound bend and arc greater than 180° should be avoided.Excessive arc not only makes the tooling bulky, but also restricted by the size of the pipe bender machine tool;Arbitrary curve, compound bend design modeling is very unreasonable, some hamper mechanization, automation production, so that the operator is difficult to get rid of heavy physical labor;Arc greater than 180° makes it impossible for the bender to unload the mould.

The bending radius of the pipe bender should be as far as possible to achieve "one tube and one mould" and "multiple tubes and one mould".For a pipe, no matter how many bends there are and how the bending Angle is, the bending radius can only have one, because the pipe bender does not change the module in the bending process, which is "one tube with one mold".And "multi-tube one mold", that is, the pipe with the same diameter specification should be used as far as possible the same bending radius, that is, the use of the same set of modules bending different shapes of pipe, so as to help reduce the number of modules.

The bending radius of the pipe determines the resistance of the steel pipe when it is bent.Generally speaking, the pipe diameter is large, the bending radius is small, the bending is easy to appear wrinkle and skid phenomenon, the bending quality is difficult to guarantee, so the general selection of the R value of the bending die is 2-3 times the pipe diameter as well.

The main influence of bending forming speed on forming quality is: the speed is too fast, easy to cause the flat bending part of the pipe, the roundness can not meet the requirements, resulting in the pipe crack, pull off;The speed is too slow, it is easy to cause the wrinkle of the conduit and the slip of the pressing block. The large diameter pipe is easy to form the sag of the bending part of the steel pipe.In view of the large number of tests on the two pipe bender, it is appropriate to determine the bending speed of the steel pipe as 20%-40% of the machine's maximum bending speed.

In the bending process, the mandrel worn by the pipe bender mainly plays the role of supporting the inner wall of the bending radius of the pipe to prevent its deformation.If the mandrel is not used in the bending forming of the pipe on the machine tool, its quality is difficult to guarantee.There are many forms of mandrel, such as column mandrel, universal single, double, three, four ball head mandrel, directional single, multi ball head mandrel.In addition, the position of the mandril also has an effect on the bending of the steel pipe: theoretically, its tangent line should be flush with the tangent line of the bending die, but after a lot of tests, it has been proved that 12mm in advance is better, and the quality of the bending pipe is ideal at this time.Of course, too much advance will cause uneven phenomenon of the outer wall of the curved part.

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