Learn the Basics of Aluminium Extrusion Bending
An incredible amount of finesse and skill goes into the process of aluminium bending. Many factors go into what is possible and what will cause problems. Today we have decided to break down a few of the key design features that affect the bending process. There are still many other factors that will not relate to every project but must still be considered.
Aluminium Extrusions – Design for Bending
The first, and possibly most important aspect is the design of the aluminium profile. This is usually created by a design engineer that most companies will never have spoken to. The designer would have had reasons for creating specific shapes and supports. However, these designers will rarely consider if the profile will be curved. This means that certain profiles are designed in such a way that bending is made incredibly difficult. On the other hand, certain profiles are designed in such a way that bending is simple and quick.
Picking the correct profile can lead to lower costs, easier bending and a shorter lead times.
However, we know that you cannot always choose which profile is to be used. Sometimes customers insist on something specific, or only one design will fit a build. In these cases, it usually comes down to the skill of the aluminium bending engineer. As well as the technology that they have on hand.
A skilled bending engineer can bend almost any profile. The only limit is the radius.
There are projects where custom made profiles are to be used and these offer the greatest opportunities for improvement. Collaborating with a skilled aluminium bending company will allow your custom extrusion to be purpose made for the best possible bending results. Design choices like making a profile symmetrical can reduce common issues like twisting and can reduce tooling costs overall.
Small adjustments to the profile design can have a massive impact on the overall bending of an aluminium extrusion.
A simple mistake many people make is believe that simple or uncomplicated extrusions are always easier to bend. These sections are often deceivingly complicated when put under the strains of the bending process and are often more prone to difficulties caused by their basic shapes. Common deceptive sections include:
Bending Aluminium Channels
U channel extrusions are some of the most difficult aluminium profiles to bend. They fall into a number of design pits that make them deceivingly complicated to bend. Their asymmetrical nature, lack of internal support and open ends make them incredibly prone to deformation no matter how you bend them. We have previously gone into detail on the difficulties of bending channel sections and you can read more about Bending Aluminium U Channels Here.
Hollow Squares and the Corner Curse
The process of aluminium section bending means that maintaining perfect 90˚ internal corners is a very difficult ask. The sharp corners lead to cracking and often push the profile to buckle and become concave. These issues mean that extra engineering has to be put into precise tooling that can provide the aluminium box section the support it requires to be curved smoothly, cleanly and without distortions. A number of filling, clamping and guiding methods are used to maintain the shape of the extrusion while providing smooth curves.
H or I Beams
H beam sections are some of the most prone to twisting extrusions you will find. Depending on the bending direction the ‘legs’ of the H will try to kick out of buckle in, often twisting the internal support in the process. These sections are often used for structural purposes, meaning these deformations must be controlled to ensure the structural stability of the piece. For this reason, many aluminium bending companies will not support bending structural H sections. Our engineers and techniques, which have been specially designed to mitigate the twisted and deformation during bending, have been certified to EN1090-3 standards, meaning we can take on these jobs where others could not.
The Impact of Profile Length
Something many people forget is that the longer an unbroken section, the more difficult every simple process becomes. For this reason, each company will have a different length of extrusion that they can support. At Alubend, we support sections up to 12 meters long for our processes. This includes bending, welding, heat treating, powder coating, and many other services. Longer sections do require special gear and considerations including extra supports, large capacity ovens and extra capacity couriers.
These sections often also require additional hands as parts become cumbersome to work with and move about. Often a simple to bend profile can become more complicated and costly to work with when dealing with extra long lengths. A simple consideration is to cut the pieces down for production and reassemble the sections once most of the processes are complete. A skilful welder can blend the sections to the point where connections become invisible.