Types of Bending
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
Rotary draw bending is used when the applications become more challenging e.g. tighter bending radii, compound bends, several bends on different radii etc.
The tube is clamped against a bend former, the clamp and the former both rotate, drawing the tube around the former. In addition, the pressure die applies pressure on the tube at the tangent of the former and follows the tube as the former and clamp rotate, this acts as reaction die/surafce thus keeping the tube to the shape of the former.
Rotary draw bending allows for more control during the tube bending process which enables the production of severe bends whilst maintaining the high quality required. This type of bending allows use of a mandrel and wiper die which are used to eradicate wrinkles on tight radii and minimises the ovality of the tube.
Roll forming is a type of free-form bending. There is typically a bend die roller, clamp roller and two pressure die rollers.
The radius of the bend is determined in relation to how far the clamp axis moves past the neutral point of the bend die roller. It is a quick and effective method of forming extremely thick walls and large radii that exceed the capacity of rotary draw benders. The collet can also be used to rotate during the roll form to create three-dimensional roll forms.
Compression bending is slightly more complicated. The tube is clamped against a stationary bend former and the pressure die follower sweeps the tube around the bend former to form the bend.