Engineers and designers are often faced with interesting challenges, when asked by project developers to create structural elements. These elements can be fundamental to the structure itself and able to bear heavy loads, or they may simply be aesthetic. Either way, the experts have to figure out how to create them by bending the raw material. When is it necessary to use heat as part of the bending process and for what reason?
Weighing up the Options
Much of the decision will be dictated by the end use for the structure. If it is to be load bearing, such as beams that support an underpass or railroad rails as examples, then much attention has to be paid to the integrity of the product once it has been engineered. This is not such an important consideration, of course, for purely architectural shapes, even though those can be a lot more challenging when it comes to bending and shaping.
Special machinery is often required for structural bending and different types of machine can be almost infinitely configured for varying thickness, spacing and make-up. The most economic approach however is to "cold" roll the material, with the objective of achieving minimum distortion as the finished result.
Here, much will also depend on the size, shape and weight of the products to be bent. It may be more economical, or certainly more practical to do this by induction, or by selective use of heat. In this case, an electrical coil (which is set up in the shape of the material being worked on) is wound around the structure. It has to be built specifically for the job and laid out very precisely. When set out in this way and activated, a precise amount of heat is transferred, or "induced" into the structure under a very high power. The more difficult the challenge, the more electricity in the form of kilowatts need to be generated to begin the bending process. As this is going on, water is sprayed onto the material during the bending process.
As you can imagine, this requires a very precise process where the temperature, air-flow over the product, the amount of cooling water and the speed of progression are critical factors. However, when this is done right, material can be bent into very precise shapes with low distortion, even using materials that would be destroyed in more traditional, cold bending.
There are other considerations to bear in mind, including the ability to carefully support the shapes when they are being worked on and how the finished product is going to be transported to the end location afterwards. It's best to discuss the various options with engineers who are skilled in this area.