How many passes does it take to bend a wide-edged steel beam
A question often asked by those unfamiliar with the operation of section bending machines (also known as angle rolls, angle cone rolls or triple roll benders) is how many passes (rolling back and forth) wide flanges are required to roll a bend The beam reaches the specified radius. Those who seek to achieve the highest productivity on these machines ask a related question: Can you achieve the required radius in one machining?
The number of passes required depends in part on the machine performing the bending. Modern press brakes allow precise and repeatable setting of tools. Unlike the old machine which may have some "play" on the shaft, the new machine has a compact structure with multiple main rollers and alignment rollers for maximum control.
The number of passes required also depends on the skill of the operator. Rolling is not just an art, but a science. After years of experience, a skilled operator can bend the steel very close to the required radius even with a single pass. Even so, it still depends on the required tolerances.
Finally, the number of passes required usually depends on the dimensional tolerances of the profile being rolled. For example, beams with a nominal depth greater than 12 inches have a tolerance of +/- 1/8 inch at the centerline of the web. And the operator knows from experience that, for example, even the beams generated by the same steel plant and the same heat, the size may be very different. In addition, even under the same heat, the physical and chemical properties of the steel beam may vary from beam to beam. Experience also tells us that even in a single beam, there may be changes in size as well as physical and chemical changes. Even with the best machinery and the best operator, this change may increase the number of passes required to achieve a tight tolerance radius.
Therefore, it is common to see the beam bend in 2, 3, 4, or 5 passes, depending on the above factors. However, in almost every case, by using a multi-pass procedure with the best equipment and skilled operators, an excellent bending effect can be achieved.