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4 Reasons Pre-Bending is Crucial When Selecting an Angle Roll Machine

angle roll

Unbent Flat Of Roll Bending Angle Iron

Again, typically a roll shop that bends a small workpiece on a large section bending machine must factor in a long flat section, which increases material costs.

After bending due to the position of the rollers on the angle steel inevitably remains a flat angle at the ends of the angle iron. This flat part is approximately half the length of the gap between the centers of the lower rollers.

Although the appearance of a straight part is considered to be a flaw of symmetrical roller with 3 roll section bending machine, their simple structure, comfortable use, and low price still make them the most wanted model of roll profile metal section bending machines.

Read More: How to bending angle iron

How To Reduce The Flat Part In Bending?

In addition, there are methods which we can use in order to easily eliminate this problem. You can find some of them below:

Pre-bending: this solution involves bending the edges of the workpiece on a press brake before the roll bending process.


Adding a “base” for the workpiece during the pre-bending: this method involves the installation of a “base” together with a workpiece designed for bending and performing the edge pre-bending process on the circular bending machine itself. The application of this method should take into account the possibilities of the circular bending machine and calculate the strength of the applied force on the “base” and the workpiece.

BIT’s section bending machines have independent motion of the two side rolls allowing the operator to minimize the sacrificial unbent flat sections on the workpiece.

But because the BIT angle rolls (profile bending machines) move the way they do, an operator can move a joystick or push a few buttons on the control to reconfigure them into a smaller-machine orientation. Beyond this, operators can fine-tune the roll position to minimize the unbent flat even further.

What Is Pre-Bending In Angle Bending Process?

Pre-bending refers to holding an angle iron firmly between multiple rolls and pushing it to create the initial bend. With the rotation of the rolls on the angle roll machine(aka angle bending machine, angle roll, angle roller), the material is fed through the rolls and once the 360-degree rolling process is completed, the pre-bent end of the angle iron makes it very easy to connect the 2 ends, thanks to the pre-bending process.

Read More: Angle Bending Process, Angle Bending Machine – 2023 Guide

4 Reasons Pre-Bending is Crucial When Selecting an Angle Roll Machine

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Reasons 1#: Eliminates Waste

The pre-bending process helps minimize waste by creating an optimum geometrical formation so that both ends of the angle iron can get in touch after rolling as perfectly as possible. Practicing the pre-bending process while having an experienced and skilled angle roll machine operator plays a very critical role in eliminating waste.

Reasons 2#: Eliminates the Need for Extra Trimming

The resources used on extra material trimming in angle iron rolling are nothing to be ignored for any efficiently and effectively functioning fabrication shops or operations. The need for extra trimming can easily be avoided through pre-bending by forming an optimum alignment of both ends of an angle iron after rolling the material.

Reasons 3#: Saves Time

Especially for high-volume production shops, wasting a minute out of the production time means wasting money and can add up quickly over time. Since pre-bending helps an operator to form the desired shapes faster, the operating time per angle iron on an angle roll machine(angle roller) diminishes, which means rolling more parts with less time.

Reasons 4#: Smooth Bending Surface and Uniform Curvature / Thickness

The pre-bending process is one of the most important practices in angle iron rolling when it comes to being able to get the results that were initially intended to get, which is simply roll bending the material correctly. The properly rolled angle iron will inevitably result in a smooth material surface and uniformity in material curvature and thickness.

Angle Iron, also known as L-bracket or angle Iron, is a 90° metal bracket that is often used in roof trusses. On support beams and structural platforms, Angle steels can also provide reliable stability and corrosion resistance.

Read More: Angle Roll Machine, Angle Roller – CNC Complex Shape Bending