The process of tube bending involves using mechanical force to push stock material pipe or tubing against the bend former or through rollers.
The Unison equipment range is based on rotary draw bending, roll forming and compression bending.
Rotary draw bending is used for more demanding tube bending applications, such as tight bend radii, compound bends, and multiple bends on different radii, where a high level of accuracy and control is required.
In this process, the tube is clamped against a bend former (bend die). Both the clamp die and bend former rotate together, drawing the tube around the former to create the bend.
A pressure die applies controlled force to the tube at the tangent point of the former and follows the tube throughout the bending cycle.
This acts as a reaction surface, helping to maintain contact between the tube and the bend former and ensuring the bend accurately matches the programmed geometry.
Rotary draw bending provides significantly greater control over the forming process compared to compression or roll bending, enabling the production of severe bends while maintaining high dimensional accuracy and surface quality.
This method also allows the use of mandrels and wiper dies, which are critical for preventing wrinkling on tight radii, controlling wall thinning, and minimising ovality of the tube cross-section.
Roll forming, also known as roll bending, is a type of free-form tube bending process used to produce large radii and complex curves.
The process typically uses a combination of rollers, including a bend die roller, a clamp roller, and two pressure die rollers. As the tube passes through the rollers, controlled pressure is applied to gradually form the desired radius.
The radius of the bend is determined by how far the clamp axis moves beyond the neutral point of the bend die roller. Adjusting this position allows a wide range of bend radii to be produced without changing tooling.
Roll forming is a fast and effective method for bending thick-walled tubes and producing large radii that exceed the capabilities of conventional rotary draw bending machines.
In addition, the collet can be rotated during the roll forming process to create three-dimensional roll-formed shapes, enabling more complex geometries in a single operation.
Compression bending is a tube bending method in which the tube is clamped against a fixed bend former, and a pressure die follower pushes the tube around the former to create the bend.
During the process, the tube is held firmly in position while compressive force is applied to shape it to the required angle and radius. Unlike mandrel bending, compression bending does not provide internal support to the tube, making it best suited to applications with larger bend radii and thicker-walled materials.
Compression bending is commonly used for simpler tube geometries where tight tolerances, minimal ovality and internal surface quality are less critical.
This method is widely applied in applications such as furniture frames, handrails, general fabrication and decorative tubing, where speed and simplicity are important.
