There are various methods for pipe bending. According to different bending methods, it can be divided into winding bending, pushing bending, pressing bending and rolling bending. According to the heating or not during bending, it can be divided into cold bending and hot bending. Divided into core (filled) elbows and coreless (filled) elbows. The following briefly introduces the various methods: according to the bending method.
1) Turn around
Bending is one of the most commonly used pipe bending methods. It is divided into two types: manual pipe bending and dynamic pipe bending. Manual pipe bending is a simple pipe bending device to bend the pipe, generally small diameter (pipe outer diameter D≤20mm). Due to the small bending moment, cold bending is used for pipes, while larger diameter pipes are mostly used for hot bending or hydraulic and electric driven pipe bending. Manual pipe bending does not require special pipe bending equipment. Because of its low manufacturing cost, It is also easy to adjust and use, so it is suitable for small batch production without special pipe bending equipment.
Generally, the servo motor or hydraulic system is used to provide power for the forced bending of the pre-bent pipe. The pre-bending angle is determined by the required forming radius of the pipe. Then, the moving trolley on the bed provides the pushing force to press the pipe longitudinally. A method of forcing the pipe to be formed by the position of the pre-bent rollers is a newer method of pipe bending, especially when bending small curvature pipe fittings. This method is particularly superior, not only can save a lot of raw materials but also Unexpected interference can be avoided. As a newer pipe bending method, its development is immature, and there is no empirical formula for the power required for pushing.
Bending is one of the earliest methods used for pipe bending. It uses two straight molds to bend the blank at the same time. This method of bending can not only process pipes with straight sections, but also bend bending. At present, press bending is widely used in pressing elbows, and it is quite common in the process of pressing elbows.
Roll bending is a method of processing the pipe under the rolling pressure of three driving rollers. The rolling principle is basically the same as the working principle of the bending machine and the rolling principle of the sheet. The only difference is the roller used for rolling the pipe. It has a working surface that matches the shape of the curved tube blank; by changing the interval of the rollers, it can be bent with any curvature radius. The roll bending method has a certain limit on the bending radius, and is only suitable for thick-walled pipe parts with large curvature radii. It is especially convenient for bending ring or spiral pipe fittings.