Before introducing how do the pipe and tube bending machines work, let's first understands the five factors: tube type regularization, bending radius standardization, bending radius, bending forming speed, mandrel, and its position. These five factors are helpful to understand the working principle of the metal pipe and tube bending machines and avoid abnormal bending of the pipe bending machine.
Avoid excessive arcs, arbitrary curves, compound bends and arcs greater than 180 °, when designing and exhausting pipes. Excessively large arcs not only make the tooling bulky but also are limited by the size of the tube and pipe bender tool. The design of arbitrary curves and compound bends is very unreasonable, which greatly hinders mechanization and automated pipe bending machine production, making it difficult for the operator to get rid of cumbersome manual labor. The arc greater than 180 ° bender makes the pipe tube bender unable to remove the mold.
The bending radius should try to achieve "one tube and one die" and "multiple tubes and one die". For a pipe, no matter how many bends and bending angles, its bending radius can only be one, because the metal pipe and tube bending machine does not replace the module during the bending process, which is "one pipe and one mold". "Multiple tubes and one mold" mean that tubes of the same diameter should use the same bending radius as far as possible, that is, using the same set of modules to bend different shapes of tubes, so as to help reduce the number of modules.
The size of the bending radius of the catheter determines the amount of resistance the catheter experiences when bending. Generally, Large diameter and the small bending radius is a good match. It is easy to wrinkle and slip when the diameter is small diameter and the bending radius is large. And the bending quality is difficult to guarantee. Therefore, the radius of the pipe bending die is generally 23 times the diameter of the pipe.
The bending forming speed is the main factor affecting the forming quality. If the speed is too fast, it will easily cause the flat part of the catheter part, and the roundness will not meet the requirements, causing the catheter to crack and break. If the speed is too slow, it is easy to cause the wrinkle of the catheter and the compression block to slip. The tube with a large diameter is easy to form the sag of the curved part of the catheter. According to a large number of tests on CNC pipe bending machines, it is appropriate to determine the bending speed of the catheter as 20%-40% of the maximum bending speed of the machine.
During the bending process, the bender mandrel mainly plays the role of supporting the inner wall of the bending radius of the catheter to prevent its deformation. If the mandrel is not used for bending the pipe material on the machine tool, its quality is difficult to guarantee. There are many types of mandrel, such as column mandrel, universal single, double, three, four ball head mandrel, oriented single, multi-ball head mandrel, etc.
In addition, the position of the mandrel also has a certain effect on the metal pipe bender. Theoretically, bending of the catheter, its tangent should be flush with the tangent of the bending die. However, a large number of tests have proved that 1 to 2 mm in advance is better, at this time the quality of the bending tube Ideal. Of course, too much advancement will cause the so-called "goose head" phenomenon on the outer wall of the curved part.
Knowing the above five factors, the following is a detailed introduction to how the pipe and tube bending machines works.
When the metal pipe bending machine bends the pipe, the rocker arm bears the circumferential force and resistance moment, and the return position of the rocker arm is dragged by the rocker arm driving device, and the return speed is 2.2 r / min. When the bending radius of the rocker swing device is adjusted, the hydraulic motor of the middle slide table is started, the worktable of the middle slide table is moved, and the center of the chuck is positioned at a specified size through the scale of the slide table, and the bending hydraulic motor is turned off.
Through the rack and pinion mechanism, move the small slide table, fix the small slide table on the middle slide table with positioning pins, rotate the top screw, and tighten the chuck to complete the positioning of the chuck; start the large slide motor and move the large slide workbench, make the center of the chuck coincide with the center of the guide wheel device, and turn off the motor; start the clamping cylinder motor to clamp the workbench of the large slide table to achieve the positioning of the workbench (rocker arm rotation center).
When the pipe is bent, the rocker arm driving device does not work, and the rocker arm slewing device is pushed by the main driving device through the pipe fittings and bears the circumferential force and resistance torque. The return position of the rocker arm is dragged by the rocker arm drive device. During bending round or square pipes, the electromagnetic clutch is closed to start the return hydraulic motor. The rocker arm drive device drives the slewing device to rotate. After the rocker arm returns to the original position, the hydraulic motor is turned off and the electromagnetic is disconnected. Clutch, ready for the next action. Pushed by the pipe fittings to bear the circumferential force and resistance torque. The return position of the rocker arm is dragged by the rocker arm drive device. During operation, the electromagnetic clutch is closed to start the return hydraulic motor. The rocker arm drive device drives the slewing device to rotate. After the rocker arm returns to the original position, the hydraulic motor is turned off and the electromagnetic is disconnected. Clutch, ready for the next action.
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